v DEPARTMENT OF AGRICUL I URE 
 DIVb IMOLOGT BULLETN 
 
 THE MEXICAN COTTON WILL WEEVIL. 
 
 PREPARED UNDER THE DIRECTION* OP THE ENTOMOLOGIST 
 
 W. I). H INTER and \Y. E. HINDS. 
 
 WASHINGTON: 
 
 GOVKRN'M E N T PRINTING OFFICE. 
 I904. 
 

 DIVISION OF ENTOMOLOGY. 
 
 L. O. Howard, Entomologist. 
 
 C. L. Marlatt, in charge of experimental field work. 
 F. H. Chittenden, in charge of breeding experiments. 
 A. D. Hopkins, in charge of forest insect investigations. 
 Frank Benton, in charge of apiculture. 
 
 W. D. Hunter, in charge of cotton boll weevil investigations. 
 A. L. Quaintance, in charge of bollworm investigations. 
 
 D. W. Coquillett, Th. Pergande, Nathan Banks, assistant entomologists. 
 
 E. A. Schwarz, E. S. G. Titus, investigators. 
 
 Miss H. A. Kelly, special agent in silk investigations. 
 
 R. S. Clifton, F. C. Pratt, August Busck, Otto Heidemann, A. N. Caudell, 
 
 J. Kotinsky, H. S. Barber, assistants. 
 W. E. Hinds, W. F. Fiske, G. H. Harris, H. E. Burke, A. W. Morrill, J. C. 
 
 Crawford, Jr., A. A. Girault, C. T. Brues, F. C. Bishopp, Springer Goes, 
 
 C. M. Walker, temporary field agents. 
 Miss L. L. Howenstein, artist. 
 
Digitized by the Internet Archive 
 
 in 2012 with funding from 
 
 University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation 
 
 http://archive.org/details/mexbolOOunit 
 
Bui. 45, Div. of Entomology, U. S. Dept. of Agriculture. 
 
 Plate I. 
 
 Developmental Stages and Work of the Boll Weevil. 
 
 Pig. 1. Cotton boll weevil: tig. 2, weevil feigning death: tig. 3, two eggs and feeding excavation 
 in a square; fig. 4, full-grown larva: tig. 5, pupa, ventral view; lii,--. 6, pupa, side view: figs. 7-9 
 show transformation taking place within squares: fig. 7, larva, full grown: rig. S, pupa; fig. 9, 
 adult; fig. 10, weevils feeding on boll: rig. 11. larva developing in boll. (Figs. 1-10, natural 
 size; fig. 11, two-thirds natural size.— Original. ) 
 
I . S. DEPARTMENT OF AGRICULTURE 
 
 DIVISION OF BHT0MOL0OT BULLETW No. 16. 
 
 l.. o. ii»>\\ \ i ; i ». Entomolooiht. 
 
 THE MEXICAN COTTON BOLL WEEVIL. 
 
 PREPARED UNDER THE DIRECTION OF THE ENTOMOLOGIST 
 
 BY 
 
 W. I). HUNTER and W. E. HINDS. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OFFICE. 
 I904. 
 
LETTER OF TRANSMITTAL 
 
 U. S. Department of Agriculture, 
 
 Division of Entomology, 
 Washington, D. C, February 20, 1904. 
 
 Sir: I have the honor to transmit herewith for publication an 
 account of the Mexican cotton boll weevil, prepared under my direc- 
 tion by Messrs. TV. D. Hunter and W. E. Hinds, special field agents 
 of this Division. Mr. Hunter has been engaged for three years in 
 investigations of this very important injurious insect, his work extend- 
 ing all through the infested portions of Texas and to some extent into 
 Mexico. Mr. Hinds for two years has been devoting his whole time 
 to this subject, having been stationed for the most part at Victoria, 
 Tex. , in charge of laboratory work. The bulletin as a whole is a 
 remarkably careful and complete treatment of the entomological 
 aspects of the investigation. It seems to me as complete a treatise of 
 the life history of a single species as has ever been published. The 
 necessity for the most perfect knowledge of eveiy detail of the habits 
 of this great enemy to the cotton crop must be obvious, since only 
 upon such perfect knowledge can we authoritatively base remedial 
 work and can we authoritatively indicate the uselessness of many of 
 the remedies proposed by ingenious and inventive persons. The six- 
 teen half-tone and other plates and six text figures are an essential 
 part of the report. 
 
 I recommend the publication of this paper as Bulletin No. 45 of 
 this Division. 
 
 Respectfully, L. (). Howard, 
 
 Entomologist. 
 
 Hon. James Wilson, 
 
 Secretary of Agriculture. 
 
PR EFACE. 
 
 The .Mexican cotton 1><>I1 weevil (Anthonomus grandis Boh.) has fche 
 unique record of developing in less than twenty years from a most 
 obscure species to undoubtedly one of the most important economic- 
 ally in the world. It was first brought to the attention of the Divi- 
 sion of Entomology as an enemy of cotton in Texas in L894. Before 
 it had invaded more than half a dozen counties in the oxt reme southern 
 portion of Texas several entomologists were sent to the region in con- 
 nection with this work. Enough was soon discovered to indicate the 
 mosl feasible plans for avoiding damage by the pest. These original 
 plans, based upon investigations of the life history of the insect, with 
 modifications, for the most part due to climatic conditions in regions 
 quite dissimilar to the lower portion of Texas, are still the basis for 
 all that is known in combating the pest. However, at that time it 
 was necessary to pay particular attention to the immediate economic 
 phases of the problem, and a detailed study of the habits of the insect 
 was impossible. In 1902, by the aid of a special appropriation by 
 Congress, it became possible to establish a complete field laboratory 
 in the portion of Texas in which the weevil had been known to exist 
 at that time for about eight years, where a careful investigation could 
 be conducted regarding the points in the life history of the pest that 
 offered even remote chances of suggesting means of avoiding damage. 
 The results of the work at this laboratory that have been of more 
 immediate economic bearing have already been published in farmers' 
 bulletins of this Department. However, as will be seen from the fol- 
 lowing pages, a very large mass of information concerning all the 
 habits of the boll weevil has been accumulated. Not only on account 
 of the great economic importance of the problem and the demand for 
 information from numerous quarters concerning the biology of the 
 pest, but also on account of the fact that the methods followed in, this 
 work have been to some extent original, and may be of use in con- 
 nection with the investigation of other insects, it is thought advisable 
 to publish a great number of the observations that have been made. 
 
 The historical and economic features, to which reference has been 
 made elsewhere in the publications of the Division, are included to 
 bring together in convenient form practically all that is known regard- 
 
 3 
 
ing the species. Much information obtained by the earlier investi- 
 gators of the Division of Entomology, Dr. L. (). Howard, Mr. C. L. 
 Marlatt, Mr. C. II. T. Townsend, and Mr. E. A. Schwarz, has been 
 used. On account of the painstaking character of the work of Mr. 
 Schwarz, and liis intimate knowledge of related species, his reports, 
 largely unpublished, have been found especially valuable. In pre- 
 senting this work the authors have taken care to state fully the data 
 furnishing the basis for the various conclusions. Under each impor- 
 tant heading will be found, first, a description of the methods and 
 apparatus employed; second, a full and in many cases tabular state- 
 ment of observations; third, the obvious conclusions. Care has con- 
 stantly been exercised to avoid errors likely to result from artificial 
 conditions in the laboratory. A large part of the work of the past 
 year was in ascertaining how closely laboratory results corresponded 
 to the actual conditions in the field. The writers have on many occa- 
 sions been surprised to discover how close the correspondence is, and 
 consider that the demonstration on a large scale of the possibility of 
 accurately determining the details of the life history and habits of an 
 insect by laboratoiy investigations is by no means the least important 
 of the results of the investigation. 
 
 The laboratory work which has led to this paper was planned origi- 
 nally by the senior author, who has also supervised the later develop- 
 ments of it. However, practically all the labor of conducting the 
 experiments and observations lias devolved upon the junior author, 
 who has suggested from time to time man} 7 important modifications of 
 the original plan. Specifically, all of the bulletin except the first por- 
 tion, dealing with historical matters, the destructiveness of the pest, 
 and the prospects, and the last portion, dealing with methods of com- 
 bating it, was written by the junior author, although revised in some 
 particulars after it had been submitted by him. The illustrations 
 used are from photographs taken for this work by the junior author, 
 with the exception of the text figures and the illustrations of insects 
 often mistaken for the boll weevil, of which those marked "original" 
 are, with one exception, from drawings prepared by Miss L. L. How- 
 enstein, one of the artists of the Division of Entomology. 
 
CONTENTS. 
 
 I'HL"\ 
 
 Qeneral considerations .._.. 11 
 
 Historical 11 
 
 1 Vstructiveness - 14 
 
 Territory affected 10 
 
 Prospects 18 
 
 Life history 20 
 
 Summary 20 
 
 The egg 20 
 
 Embryonic development . _ _ . 21 
 
 Length of egg stage 21 
 
 Hatching 22 
 
 Eating of eggs deposited outside 22 
 
 Percentage of eggs that hatch 23 
 
 The larva 23 
 
 Description 23 
 
 Growth 24 
 
 Molts 24 
 
 Process of molting ... 24 
 
 Length of larval stage 25 
 
 Pnpal cells in bolls 26 
 
 Pupation 26 
 
 The pupa 26 
 
 Length of pupal stage 27 
 
 Effect of burying squares upon pupation and the escape of adults. . 28 
 
 The adult 29 
 
 Before emergence 29 
 
 Emergence 29 
 
 Changes after emergence 29 
 
 Size of weevils . __ . 30 
 
 Relation of size to food supply 30 
 
 Weight of adults 30 
 
 Color 31 
 
 Size and color not indicative of sex 31 
 
 Proportions of the sexes 32 
 
 Length of life upon squares . _ 33 
 
 Length of life on bolls alone . 34 
 
 Length of life on cotton leaves alone _ _ . . . 34 
 
 Length of life with sweetened water and with molasses . 33 
 
 Length of life without food, but with water 3o 
 
 Length of life without food or water 35 
 
 Cannibalism 36 
 
 5 
 
Hal )its . 
 
 Food habits 
 
 Larval 
 
 Adult 
 
 Male 
 
 Female 
 
 Males and females together 
 
 Feeding of hibernated weevils on early cotton 
 
 Increase in leaf area of cotton . 
 
 Effects of feeding upon squares and bolls 
 
 Destructive power by feeding 
 
 Susceptibility of various cottons ... 1 
 
 Has the weevil any other food plant? 
 
 Insects often mistaken for the boll weevil 
 
 Is cotton-seed meal attractive ? 
 
 Laboratory observations 
 
 Field tests 
 
 The possibility of baiting weevils with sweets 
 
 Attractiveness of various sweets 
 
 Attractiveness to hibernated weevils in laboratory _ _ . 
 
 Influence of sweetened water upon feeding of weevils on cotton 
 
 plants . . . . . 
 
 Field tests for hibernated weevils, using pure molasses 
 
 Feigning death 
 
 Reproduction 
 
 Method of making field observations upon work of weevils 
 
 Fertilization 
 
 Age of beginning copulation 
 
 Sexual attraction and duration of copulation . 
 
 Duration of fertility in isolated females 
 
 Oviposition 
 
 Age of beginning oviposition 
 
 Examination of squares before oviposition . 
 
 Selection of uninf ested squares for oviposition 
 
 Laboratory observations 
 
 Field observations 
 
 Activity of weevils in different parts of the day 
 
 Place of egg deposition. 
 
 Position of weevil while puncturing for oviposition : _' 
 
 The act of oviposition 
 
 Time required to deposit an egg 
 
 Rate of oviposition — average, maximum 
 
 Stimulating effect of abundance of squares on egg deposition 
 
 Relation of warts to oviposition 
 
 Effects of oviposition upon squares — flaring, falling 
 
 Period of oviposition 
 
 Does parthenogenesis occur ? 
 
 Development 
 
 Percentage of weevils developed from infested squares 
 
 Development of weevils in squares which never fall 
 
 Length of life cycle 
 
 Broods or generations 
 
 Page. 
 36 
 37 
 37 
 37 
 39 
 39 
 40 
 40 
 41 
 43 
 44 
 44 
 47 
 48 
 50 
 50 
 51 
 52 
 52 
 53 
 
 54 
 55 
 
 :>c> 
 56 
 56 
 57 
 57 
 57 
 58 
 58 
 58 
 59 
 59 
 60 
 61 
 63 
 65 
 65 
 66 
 67 
 
 69 
 70 
 72 
 72 
 73 
 73 
 73 
 74 
 75 
 
I )r\ el< ipmenl ( \ »nt inued. 
 
 Thermal influence upon activity and development 
 
 Laboratory experiment in effect of temperatnre upon locomotive 
 
 activity 
 
 Hibernation 90 
 
 Length of hibernat ion period 82 
 
 Apparently favorable conditions for hibernation s: '> 
 Percentage of weevils hibernating successfully 
 
 Seasonal hist* >ry 8 1 
 
 Emergence From hibernat ion M 
 
 Apparent dependence of reproduction upon food obtained from squares 86 
 
 Progress of infestation in fields 86 
 
 Weevil injury r. square production .. 88 
 
 Relation of weevils to " top crop " - '-'i 
 
 Some reasons for early destruction of stalks ... 92 
 
 Dissemination . - 94 
 
 Weevils in Beed houses at ginneries .. 94 
 
 Nat oral control . 9."i 
 
 Mechanical control . 95 
 
 Pilose obstacles to weevil progress 95 
 
 Destruction of larva and pupae in bolls and squares by abnormal 
 
 plant growth '.•<*» 
 
 Climatic control _ 97 
 
 Influence of climatic conditions upon weevil multiplication and 
 
 injury 97 
 
 Effect < »f rains upon development of weevils 98 
 
 Effects of wet winter weather on hibernating weevils 99 
 
 Effects of overflows in fields 99 
 
 Laboratory observations upon time weevils will float and endure 
 
 submergence 100 
 
 Probabilities as to influence of climate on weevils in cotton regions 
 
 not now infested 101 
 
 Diseases 104 
 
 Parasites .__ lo."» 
 
 Breeding of parasites 105 
 
 Pediculoides ventricosus 1 . _ 107 
 
 Predatory enemies . . 109 
 
 Insects 109 
 
 Birds 110 
 
 Methods of combating the weevil .. 110 
 
 ( "ultural methods ... Ill 
 
 Futile means .... 112 
 
 Bibliography . _ 113 
 
ILLUSTRATION'S. 
 
 PLATES. 
 
 Plate I. Fig. 1.— Cotton boll weevil Frontispiece 
 
 Fig. 2. — Weevil feigning death Frontispiece 
 
 Fig. 3. — Two eggs and feeding excavation in a square - . . Frontispiece 
 
 Fig. 4. — Full-grown larva Frontispiece 
 
 Fig. 5. — Pupa, ventral view Frontispiece 
 
 Fig. G. — Pupa, side view Frontispiece 
 
 Fig. 7. — Larva, full-grown Frontispiece 
 
 Fig. 8. — Pupa Frontispiece 
 
 Fig. 9.— Adult Frontispiece 
 
 Fig. 10. — Weevils feeding on boll Frontispiece 
 
 Fig. 11 . — Larva developing in boll Frontispiece 
 
 II. Fig. 12. — Collection showing life history and work of boll weeviL _ 24 
 
 III. Fig. 13. — Two weevils feeding on a square 24 
 
 Fig. 14.— Egg isolated 24 
 
 Fig. 15. — Full-grown larva in square 24 
 
 Fig. 16.— Full-grown larva isolated 24 
 
 Fig. IT.— Pupa 24 
 
 Fig. 18. — Adult just transformed 24 
 
 Fig. 19. — Large larvae in large boll __- 24 
 
 Fig. 20. — Pupal cell in boll broken open 24 
 
 IV. Fig. 21. — Emergence hole made by weevil in square 32 
 
 Fig. 22. — Weevil escaping normally from boll 32 
 
 Fig. 23. — Apparatus used in breeding weevils 32 
 
 Fig. 24. — Larva destroying the ovary and preventing bloom in 32 
 
 large square 32 
 
 Fig. 25. — Leaf fed upon by weevils in confinement 32 
 
 Fig. 26. — Emergence hole of weevil from boll which never opened. 32 
 
 V. Fig. 27. — Larva in square, ovary untouched 32 
 
 Fig. 28. — Large and small larva? in boll 32 
 
 VI. Fig. 29.— Square much fed upon 48 
 
 Fig. 30. — Distorted bloom, caused by feeding upon large square. _ 48 
 
 VII. Fig. 31. — Blooms distorted by feeding punctures, open but imper- 48 
 
 feet . 48 
 
 Fig. 32. — Small boll riddled by feeding punctures 48 
 
 Fig. 33. — One lock of boll destroyed by feeding punctures 48 
 
 VIII. Fig. 34.— External appearance of large boll much fed upon 56 
 
 Fig. 35. — Internal appearance of same boll ... 56 
 
 IX. Fig. 36. — Cages used to confine weevils in field 56 
 
 Fig. 37. — Plant showing tagged squares from cage work 56 
 
9 
 
 IMvii x. Pig 88, Boll showing two la troyed bj two feed 
 
 punctures made bj a male wreevil 
 i . 89, Square showing externa] appearanc lof t w egg pnnc 
 
 hires :,,; 
 Fig, it i. Waii formed on side of Bqnare In healing an egg pnnc 
 
 hire :,,; 
 
 Fig. ii. Egg deposited on inside of carpel of a boll 66 
 
 Fig. Id. Normal and flared squares 56 
 
 XI. Fig, 18. Three large larvae in a boll 64 
 Fig. 1 1. — Four papal cells from bolls on left compared with four 
 
 c>t ton seeds on right 64 
 
 XII. Fig. 45. Device used to test attraction of molasses in the field 
 
 in spring . - - - 64 
 
 Fig. !»'». -Fallen squares on gronnd in field <*>l 
 
 Fig. -IT. — Squares dried and still hanging upon the plant <i I 
 Fig. 48. — Device used to test relative attractiveness t<> weevils 
 
 of American and Egyptian squares 64 
 
 XI II. Fig. 4'.).— Device used to test effect of temperature upon weevil 
 
 activity 80 
 
 Fig. 50. — Comparison of pilosity on " King " (at left I and li Mit 
 
 Ann - ' (at right) stems 80 
 
 Fig. 51. — Locality found very favorable to hibernation of many 
 
 weevils s(> 
 
 XIV. Figs. 50 and 5:5. — Mexican cotton boll weevil {Anthonomus 
 
 gran (lis) 80 
 
 Fig. 54. — Lixus sp__. 80 
 
 Fig. 55. — Acorn weevil {Balaninus uniformis auct.) a. female, 
 dorsal view: b, same, lateral view: c, head, snout, 
 
 and antenna of male 80 
 
 Fig. 56. — Apple curculio (Coccoto)-us scutellaris) Si) 
 
 Fig. 57. — Plum gouger {Anthonomus prunicida) 80 
 
 Fig. 58. — Des)noris scajxilis _•. 80 
 
 XV. Figs. 59 and 60. — Transverse Baris (Baris transversa) 90 
 
 Fig. 61. — Centrinus penicellus 96 
 
 Fig. 62. — Coffee bean weevil (Arcecerus faseiculatus): a. larva: 
 
 o, beetle; c. pupa 96 
 
 Figs. 63 and 64. — ChalcocU rmus ceneus 96 
 
 XVI. Figs. 65 and 66. — Sharpshooter (Homalorfisca triquetra) 96 
 
 Fig. 67. — Cotton stainer {Dysdercus suturellus) 96 
 
 Fig. 68. — Cotton stalk borer {Ataxia erypta).^. 96 
 
 Fig. 69. — Imbricated snout-beetle {Epiccerus imbricatus) 96 
 
 Fig. 70. — A snapping beetle (Monocrcpidins vespertinus) 96 
 
 TEXT FIGURES. 
 
 Fig. 1. Map of area infested by weevil .. 17 
 
 2. Mexican boll weevil, head showing rostrum and antenna' 38 
 
 3. Diagram showing activity of 5 female weevils . 64 
 
 4. Bracon mellitor 106 
 
 5. Enemy of boll weevil . Pedieuloides ventricosus 107 
 
 6. Solenopsis debilis var. texana 109 
 
THE MEXICAN COTTON BOLL WEEVIL 
 
 GENERAL CONSIDERATIONS. 
 HISTORICAL. 
 
 There is very Little certainty regarding the history of the Mexican 
 
 cotton boll weevil before it came to the attention of the Division of 
 Entomology in Texas in L894. The species was described by Boheman 
 
 in IS4:> from specimens received from Vera Cruz, and it was recorded 
 by SnlVrian in 1871 as occurring at Cardenas and San Cristobal in 
 Cuba. Written documents in the archives at Monclova, in the State 
 of Coahuila, Mexico, indicate that the cultivation of cotton was prac- 
 tically abandoned in the vicinity of that town about the year L848, or 
 at least that some insect caused very great fears that it would be nec- 
 essary to abandon the cultivation of cotton. A rather careful inves- 
 tigation of the records makes it by no means clear that the insect was 
 the boll weevil, although there is a rather firmly embedded popular 
 notion in Mexico, as well as in the Southern United States, that the 
 damage must have been perpetrated bj^ that species. As far as the 
 accounts indicate, it might have been the boll worm (HeLiothis armi- 
 ger) or the cotton caterpillar (Ah fia argillacea). 
 
 From the time of the note by Suffrian regarding the occurrence of 
 the weevil in Cuba in 1871 up to 1885 there has been found no pub- 
 lished record concerning it. In 1885, however, C. V. Riley, then 
 Entomologist of the Department of Agriculture, published in the 
 report of the Commissioner a very brief note to the effect that Antho- 
 nomas grand is had been reared in the Department from dwarfed cot- 
 ton bolls sent by Dr. Edward Palmer from northern Mexico. This is 
 the first account associating the species with damage to cotton. The 
 material referred to was collected in the State of Coahuila, supposedly 
 not far from the town of Monclova. The exact date at which the 
 insect crossed the Rio Grande into Texas is as uncertain as the means 
 whereby this was accomplished. All that can be found, which is 
 mostly in the form of testimony of planters in the vicinity of Browns- 
 ville, indicates that the pest first made its appearance in that locality 
 about 1802. In 1801 it had spread to half a dozen counties in the 
 Brownsville region, and during the last months of the year was 
 brought to the attention of the Division of Entomology as an impor- 
 tant enemy of cotton. Mr. C. II. T. Townsend was immediately sent 
 
 11 
 
12 
 
 to the territory affected. His report was published in March, 1895. 
 It dealt with the life history and habits of the insect, which were 
 then completely unknown, the probable method of its importation, 
 the damage that might result from its work, and closed with recom- 
 mendations for fighting it and preventing its further advance in the 
 cotton-producing regions of Texas. It is much to be regretted that 
 the State of Texas did not adopt at that time the suggestion made by 
 the Division of Entomology that a belt be established along the Rio 
 Grande in which the cultivation of cotton should be prohibited, and 
 thus cut off the advance of the insect. 
 
 The events of the last few years have verified the prediction of the 
 Division of Entomology in regard to the advance made and the dam- 
 age caused by the insect. 
 
 In 1895 the insect was found by the entomologists, who continued 
 the investigation started the year before, as far north as San Antonio 
 and as far east as Wharton. Such a serious advance toward the 
 principal cotton-producing region of the State caused the Division to 
 continue its investigations during practically the whole season. The 
 results of this work were incorporated in a circular by Doctor Howard, 
 published early in 1896, in both Spanish and English editions. 
 
 An unusual drought in the summer of 1896 prevented the maturity 
 of the fall broods of the weevil, and consequently there was no exten- 
 sion of the territory affected. It should be stated in this connection 
 that the region from San Antonio to Corpus Christi and thence to 
 Brownsville will frequently pass through similar experiences, which 
 will be quite different from anything that may be expected to occur 
 in regions where the rainfall is more certain. In 1900 as well as in 
 1903, in all or part of the region referred to, the numbers of the weevil 
 were reduced by climatic conditions, principally a scanty rainfall, so 
 that they were comparatively unimportant factors. During 1896 the 
 investigations were continued and the results published in another 
 circular issued in February, 1897. This circular was published in 
 Spanish and German, as well as English editions, for the benefit of the 
 very large foreign population in southern Texas. 
 
 The season of 1897 was in many respects almost as unfavorable as 
 that of 1896, although the pest increased its range to the region about 
 Yoakum and Gonzales. Although this extension was small it was 
 exceedingly important, because the richest cotton lands in the United 
 States were beginning to be invaded. The problem had thus become 
 so important that Mr. Townsend was stationed in Mexico, in a region 
 supposed to be the original home of the insect, for several months to 
 discover, if possible, any parasites or diseases that might be affecting 
 it, with the object of introducing them to prey upon the pest in Texas. 
 Unfortunately nothing was found that gave any hope of material 
 assistance in the warfare against the weevil. 
 
 The season of 1898 was very favorable for the insect. Bastrop, 
 
18 
 
 L©e, and Burleson counties became invaded, and some Isolated oolo 
 oies were found across the Brazos River, in Waller and Brazos coun 
 lies, investigations by the Division of Entomology were continued, 
 and a summary of the work, dealing especially with experiments 
 conducted by Mr. C. L. Marlatt in the spring of L896, was published 
 in still another circular. At this time the legislature of the State of 
 Texas made provision for the appointment of a State entomologist 
 and provided a Limited appropriation for an investigation of means 
 of combating the boll weevil. In view of this lad the Division of 
 Entomology disconl inued, temporarily, the work t hat had been carried 
 on by having agents in the field almost constantly for four years, and 
 all correspondence was referred to the State entomologist; but, 
 unfortunately, the insect continued to spread, and it soon became 
 apparent that other States than Texas were threatened. This caused 
 the work to be taken up anew by the Division of Entomology in 
 1901, in accordance with a special appropriation by Congress for an 
 investigation independent of that being carried on by the State of 
 Texas and with special reference to the discovery, if possible, of 
 means of preventing the insect from spreading into adjoining Stales. 
 In accordance with this provision an agent was sent to Texas in 
 March and remained in that State until December. lie carried on 
 cooperative work upon eight of the larger plantations in the weevil 
 region. The result of his observations was to suggest the advisability 
 of a considerable enlargement of the scope of the work. It had been 
 found that simple cooperative work with the planters was exceedingly 
 unsatisfactory. The need of a means of testing the recommendations 
 of the Division of Entomology upon a large scale, and thereby furnish- 
 ing actual demonstrations to the planters, became apparent. Conse- 
 quently, at the suggestion of the Department of Agriculture, provision 
 for an enlargement of the work was made by Congress. Agreements 
 were entered into with two large planters in typical situations for t est - 
 ing the principal features of the cultural system of controlling the 
 pest upon a large scale. In this way 125 acres at Victoria and 200 
 acres at Calvert were employed. At the same time the headquarters 
 and laboratory of the special investigation were established at Vic- 
 toria, and such matters as parasites, the possibility of poisoning the 
 pest or of destroying it by the use of machines, as well as investigat- 
 ing man}- of the features of its biology that were still absolutely 
 unknown, were given careful attention by a specially trained assistant 
 whose services were procured for that purpose. The results of the 
 field work for this }ear were published in the form of a Farmers' 
 Bulletin entitled ''Methods of Controlling the Boll Weevil; Advice 
 Based on the AVork of 1902;" but on account of the late date of the 
 establishment of the laboratory (June), and the consequent incom- 
 pleteness of many of the records, it was not thought advisable to 
 publish anything concerning the laboratory investigations. During 
 
14 
 
 this season cooperation was carried on with the Mexican commission 
 charged with the investigation of the boll weevil in that country, which 
 was arranged on the occasion of a personal visit of Dr. L. O. Howard 
 to the City of .Mexico in the fall of 11)01. Specimens of parasites were 
 frequently exchanged, and through the courtesy of Prof. A. L. 
 Herrera, chief of the Mexican commission, an agent in charge of the 
 investigation in Texas visited the laboratories at the City of Mexico 
 and Cuernevaca, where a study was made of the methods of propa- 
 gating parasites, especially Pediculoides ventricosus Newp. A large 
 number of specimens of this mite was brought back to Texas, where 
 they were carried through the winter successfully and used in field 
 experiments the following season. 
 
 The favorable reception by the planters of Texas of the experi- 
 mental field work conducted during this season, with the increased 
 territory invaded by the pest, brought about an enlarged appropria- 
 tion for the work of 1903. By enactment which became effective on 
 the 1th of March 830,000 was placed at the disposal of the Division of 
 Entomology. It thus became possible to increase the number and size 
 of our experimental fields as well as to devote more attention to the 
 investigation of matters suggested by previous work in the laboratory . 
 Seven experimental farms, aggregating 558 acres, were accordingly 
 established in as many distinct cotton districts in Texas. Despite 
 generally very unfavorable conditions the results of this experi- 
 mental work demonstrated many important points. The principal 
 ones are detailed in Farmers' Bulletin No. 189 of this Department. 
 
 DESTRUCTIVENESS. 
 
 Various estimates of the loss occasioned to cotton planters by the 
 boll weevil have been made. In the nature of the case such estimates 
 must be made upon data that is difficult to obtain and in the collec- 
 tion of which errors must inevitably occur. There is, of course, a 
 general tendency to exaggerate agricultural losses, as well as to attrib- 
 ute to a single factor damage that is the result of a combination of 
 many influences. Before the advent of the boll weevil into Texas 
 unfavorable weather at planting time, summer droughts, and heavy 
 fall rains caused very light crops to be produced. Now, however, the 
 tendency is everywhere to attribute all of the shortage to the weevil. 
 Nevertheless, the pest is undoubtedly the most serious menace that 
 the cotton planters of the South have ever been compelled to face, if 
 not, indeed, the most serious danger that ever threatened any agri- 
 cultural industry. It was generally considered, until the appearance 
 of the pest in Texas, that there were no apparent difficulties to prevent 
 an increase in cotton production that would keep up to the enlarging 
 demand of the world until at least twice the present normal crop of 
 about 10,500,000 bales should be produced. Now, however, in the 
 opinion of most authorities, the weevil has made this possibility very 
 
L5 
 
 doubtful, although the Aral fears entertained in man} localities that 
 the cultivation of cotton would have to be abandoned have generally 
 been given up. An especially unfavorable feature of the problem is 
 in the fact thai the weevil reached Texas at whai would have been, 
 from other considerations, the most critical time in the history of the 
 production of the Btaple in the State. The natural fertility of the 
 cotton lauds had been bo great that planters had neglected complete^ 
 such matters as seed selection, varieties, ferf ilizers, and rot a i ion, that 
 in usi eventually receive consideration in any cotton-producing coun- 
 try. In general, the only seed used was from the crop of the preced- 
 ing year, unselected and of absolutely unknown variety, and the use 
 of fertilizers had not been practiced al all. Although ii is by no 
 im 'a ns i rue ih.ii the fertility of the soil had been exhausted, neverthe- 
 less, <>ii many of the older plantations in Texas the continuous plant- 
 ing of cotton with a run-down condition of the seed combined to make 
 a change necessary in order to continue the industry profitably. 
 
 A careful examinal ion of the stal ist ics, to which more complete ref- 
 erence is made in Farmers' Bulletin No. 189, has indicated thai the 
 pes! causes a reduetion in production for a few years after its ad venl 
 { >[' about 50 per cent, hut at the same time it is evident that most 
 planters within a few years are able to adopt the changes in the sys- 
 tem of cultivating this staple that are made necessary by the weevil, 
 so that the damage after a short time does not compare with that at 
 the beginning. Upon the foregoing basis, during the season of 1903 
 the weevil caused Texas cotton planters a loss of about $15,000,000, 
 and tins estimate agrees rather well with estimates made in other 
 ways by the more conservative cotton statisticians. A similar esti- 
 mate made in 1902 led to the conclusion that the damage amounted 
 to about $K »,000,i »<>< i. It consequently appears that during the years 
 the pest has been in Texas the aggregate damage would reach at least 
 $50,000,000. .Many conditions of climate and plantation practice in 
 the eastern portion of the cotton belt indicate that the weevil prob- 
 lem will eventually be as serious east of the Mississippi as it now is 
 in Texas. According to the estimates of Mr. Richard II. Edmunds, 
 the editor of Manufacturers' Record, the normal cotton crop of the 
 United states represents a value of $500,000,000, the extreme ulti- 
 mate damage that the pest might accomplish over the entire belt 
 would be in the neighborhood of $250,000,000 annually, provided none 
 of the means of avoiding damage that are now coming into common 
 use in Texas were adopted. In spite of the general serious outlook, 
 however, it must be stated that fears of the damage the weevil may 
 do are very often much exaggerated, especially in newly invaded 
 regions. It is not at all necessary to abandon cotton. The work of the 
 Division of Entomology for several seasons has demonstrated that a 
 crop can be grown profitably in spite of the boll weevil, and this expe- 
 rience is duplicated by many planters in Texas. 
 
16 
 
 TERRITORY AFFECTED. 
 
 At the present time the boll weevil lias no! been found in the 
 
 Tinted States outside of Texas (see fig. 1) except in three instances 
 in Louisiana. In one of these cases, at the sugar experiment station 
 a1 Audubon Park, in the vicinity of New Orleans, the circumstances 
 have led the State authorities to the conclusion that the pests 
 purposely placed in the fields. The other two eases are isolated oc- 
 currences in Sabine Parish, in the extreme western part of the State. 
 Both of these are apparently traceable to importation from the oppo- 
 site county in Texas, in cotton seed used for planting purposes or 
 possibly in hay. The authorities totally destroyed the cotton grow- 
 ing at the experiment station at Audubon Park, La., as soon as the 
 presence of the weevils was discovered. As no cotton is grown 
 within 9 miles of that point, it seems altogether likely thai the colony 
 may have been completely exterminated. Similar action is bein. 
 taken regarding the two colonies found in Sabine Parish. 
 
 In Texas the infested area extends from Brownsville, where tin- 
 weevil originally entered the State, to Sherman. Shelby and Morris 
 counties represent the extreme eastern range. The cotton acreage 
 involved in this territory includes about 30 per cent of the cotton 
 acreage of the United States, which produced in 1900 about 35 per 
 cent of the total crop of this country, or about one-fourth of the crop 
 of the world for that j T ear. There is, however, a considerable bell 
 between about the latitude of Dallas and the Red River where th« 
 pest does not occur in uniform numbers in all cotton fields, and con- 
 sequentl} 7 the general damage has not been great. It may be a mat 1 er 
 of only two or three years before it will become sufficiently numerous 
 to cut down the total production. 
 
 There are some features of special interest in the situation in Cuba. 
 Although the weevil has long been known to occur in the island, it 
 has attracted very little attention on account of the fact that the cul- 
 tivation of cotton was abandoned for a long time in favor of crops that 
 have been more profitable. Now, however, with the better price of the 
 staple and rather unsatisfactory returns from some other crops, cot- 
 ton is being planted upon a considerable scale. Mr. E. A. Schwa rz 
 was sent to the island on two occasions to study the conditions there. 
 Although his report refers especially to the Province of Santa Clara, 
 it is probably true that conditions similar to those he describes obtain 
 everywhere. He found that the entire province is naturally more oi- 
 lers infested by the boll weevil, and that weevils did not spread from 
 cultivated cotton planted with seed obtained in the United States to 
 the wild plants, as at first supposed, but from the latter to the former. 
 The weevils were found to be more numerous on the kidne} 7 cotton 
 growing wild than on the loose cotton (seminiella). The latter, when 
 growing alone, was usually found to be free from weevils, but liable 
 to be infested when growing in the vicinity of kidney cotton. A large 
 
IT 
 
 MEXICO 
 
 Fig. 1.— Map showing area infested by Mexican cotton bull weevil (redrawn. > 
 21739— No. 45—04 2 
 
18 
 
 number of wild cotton trees growing in the vicinity of dwellings or 
 growing entirely wild are always infested, and here the weevils are 
 more numerous, bu1 never as numerous as on the cultivated Egyptian 
 cotton. Al one locality, where a large number of kidney cotton trees 
 were glowing (about 50 plants, some of them probably 20 years old), 
 il was found that at least one out of every twenty squares had been 
 punctured by the first week in March. From Mr. Schwarz's report 
 it does not seem that there is a very promising outlook for cotton 
 raising in Cuba. The presence of wild perennial cotton, upon which 
 the weevil probably exists everywhere, will always be a source of 
 danger. The long moist seasons and mild winters will form more 
 favorable conditions for the pest than will occur anywhere in the 
 United States. 
 
 PROSPECTS. 
 
 The investigations of the life history of the weevil that are referred 
 to in detail in the following pages have indicated that the most im- 
 portant elements in limiting the spread of an insect — namely, win- 
 ter temperatures and parasites — in this case offer no assurance that 
 the pest will soon be checked. For the past ten years, except where 
 local unfavorable conditions have interfered, it has advanced annu- 
 ally a distance of about 50 miles. The insect is undoubtedly chang- 
 ing its habits and adapting itself to climatic conditions in new T regions 
 that it is invading. It is undoubtedly true that it has acquired an 
 ability to withstand more severe frosts than occurred in the vicinity 
 of San Antonio in 1895. Except in a few particular regions, however, 
 it does not seem that the continued spread will be as rapid as it has 
 been. The country between Gonzales Count}* and the Red River is 
 practically a continuous cotton field, and the prevailing winds have 
 undoubtedly favored the northward spread of the insect. Similar 
 conditions will now favor a rapid extension into the Red River valley 
 in Louisiana, and likewise there seems no doubt that the spread' will 
 be rapid in the Yazoo valley in Mississippi; but in most other situa- 
 tions throughout the belt the cotton fields are smaller and more iso- 
 lated than is the case in Texas; consequently it is to be supposed 
 that the spread of the pest will be retarded somewhat. 
 
 Basing estimates on a careful study of the distance the boll weevil 
 has traveled each year, as well as upon some attention that has been 
 paid to the means wiiereb}* it reaches new territory, referred to more 
 in detail hereafter (p. 9-4), it seems safe to predict that in from fifteen 
 to eighteen years the pest will be found throughout the cotton belt. 
 During the time it has been in Texas there has been no tendency 
 toward dying out, and in south Texas the pest is practically as trou- 
 blesome, except in so far as it is affected by changes in managing the 
 crop, as it was in 1895. In Mexico, where it has existed for a much 
 longer period, it is apparently as plentiful as ever. Careful attention 
 that has been paid to the study of parasites and diseases, as well as 
 
 
L9 
 
 temperatures unfavorable to the insect, lias failed to reveal anj pros 
 peel that ii nn i 1 1 ever 1 *« * muoli less troublesome than now. There 
 will, nevertheless, be seasons from time t<> time in \\ 1 1 i «• 1 1 the damage 
 will be much less than normal. Climatic conditions will undoubtedly 
 cause temporary diminution of 1 1 1« * numbers of the pest in certain 
 localities. In Texas these conditions have given rise almost every 
 year to the supposition on the part of the planters that the insects 
 have died out. This was especially the case in the region between 
 San Antonio and Beeville in L900, and in the vicinity of Corpus 
 Christi in L903. Both these years followed a series of seasons in 
 which there was much Less than the normal rainfall; consequently not 
 only had a great many of the weevils been killed, but the numbers 
 had been diminished by reason of the very Limited extent to which LI 
 was possible to raise cotton. Both L900 and L903, however, were 
 exceedingly favorable for cotton. Early planting was possible, and 
 there was an abundance of rain throughout the season. The crop 
 was so far advanced by the time the weevils became numerous thai a 
 very fair yield was made, although in neither of the cases was any 
 top crop whatever produced. Whenever a series of years of scanty 
 rainfall is followed by one of normal precipitation the weevil will 
 temporarily be comparatively unimportant. The most disastrous 
 seasons will be those in which the rainfall is excessive and planting 
 unavoidably thrown late. 
 
 In this connection it becomes of some interest to speculate as to the 
 possibility that the weevil may eventually be carried outside of the 
 United States and gain a foothold in other cotton-prodncing countries. 
 The fact that the insect is rather rapidly adapting itself to conditions 
 in the United States that are quite diverse from those of its native home 
 leads to the supposition that it would experience but little difficulty in 
 adapting itself to climatic conditions wherever cotton may be grown. 
 This probability of the spread of the w T eevil outside of the United 
 States is increased by the fact that cotton seed for planting purposes 
 is frequently shipped from the United States to various parts of the 
 globe, and that within the last few r years various conditions have 
 caused especial interest to be displayed in this matter. There is 
 nothing whatever to prevent weevils that may happen to be sacked 
 with cotton seed from being carried long distances on shipboard. In 
 the semidormant condition in which they hibernate they have often 
 been known to go longer without food than is ordinarily required for 
 a freight shipment from Galveston to Cape Town. Although there 
 are no truly cosmopolitan cotton insects, it seems likely that the boll 
 weevil ma}* eventually be more widely distributed than any other. 
 
20 
 
 LIFE HISTORY. 
 
 SUMMARY. 
 
 The egg is deposited by the female weevil in a cavity formed by eat- 
 ing into a square or boll. The egg hatches in a few days and the 
 footless grub begins to feed, making a larger place for itself as it 
 grows. During the course of its growth the larva sheds its skin at 
 least three times, the third molt being at the formation of the pupa, 
 which after a few days sheds its skin, whereupon the transformation 
 becomes completed. These immature stages require on the average 
 between two and three weeks. A further period of feeding equal to 
 about one-third of the preceding developmental period is required to 
 perfect sexual maturity so that reproduction may begin. 
 
 Variation in size depends directly upon abundance and condition 
 of the food supply. Weevils of average size are about 8 mm. in length, 
 one-third as broad as long, and weigh about one-fourth of a grain. 
 Color varies as widely as does size. It is usually of a gray or yellow- 
 brown, and is most markedly yellow in the largest weevils. Sexes 
 are produced in practically equal numbers, the males predominating 
 slightly. No other food has been found which will attract weevils 
 from squares and no plant but cotton upon which they can sustain 
 themselves for any considerable length of time. See PI. II, fig. 12. 
 
 THE EGG. 
 
 The egg of the boll weevil is an unfamiliar object even to many 
 who are thoroughly familiar with the succeeding stages of the insect. 
 If laid upon the exterior of either square or boll it would be fairly 
 conspicuous on account of its pearly white color. Measurements 
 show that it is on the average about 0.8 mm. long by 0.5 mm. wide. 
 Its form is regularly elliptical (PI. Ill, fig. 14), but both form and 
 size vary somewhat. Some eggs are considerably longer and more 
 slender than the average, while others are ovoid in shape. The shape 
 may be influenced by varying conditions of pressure in deposition 
 and the shape of the cavity in which it is placed. The soft and deli- 
 cate membrane forming the outer covering of the egg shows no notice- 
 able markings, but is quite tough and allows a considerable change 
 in form. Were the eggs deposited externally they would doubtless 
 prove attractive to some egg parasite as well as to many predatory 
 insect enemies. Furthermore, the density of the membranes would 
 be insufficient to protect the egg from rapid drying or the effects of 
 sudden changes in temperature. All these dangers the weevil avoids 
 by placing the eggs deeply within the tissue of the squares or bolls 
 upon which she feeds. As a rule, the cavities which receive eggs 
 are especially prepared therefor and not primarily for obtaining food. 
 Buried among the immature anthers of a square or on the inner side of 
 one carpel of a boll, as they usually are, weevil eggs become very incon- 
 spicuous objects (PL I, fig. 3) and are found only after careful search. 
 
21 
 
 EMBRYONIC m:\ i:i.< >r\ii 
 
 Owing to the transparency of tli<- egg membranes, something of 
 the development of il>" embryo can !><• Been through them, but n<> 
 special stud} has yel been made upon the subject of the embryology 
 of the weevil. The fully developed embryo completely nils the inte- 
 rior of the egg, its large head being in one end and its body curved 
 vent rally upon itself till nearly double. Considerable mot ion is mani- 
 fested if the egg be touched at this period. 
 
 LENGTH <>F EGG STAGE. 
 
 Concealed as the eggs are beneath several layers of vegetable tis- 
 sue, it is impossible to examine them to ascertain the exact Length of 
 the egg stage without in some degree interfering with the naturalness 
 of the accompanying conditions. The beginning of the stage was 
 easily obtained by confining female weevils with uninfested squares. 
 Careful dissections were then made of the squares at a little later 
 than what was found to "be the average embryonic period at that sea- 
 son. In this way it is believed the range of error was reduced to a 
 fraction of a day in most cases, and a large number of observations 
 were made to still further reduce the error. 
 
 As shown by Table I, 553 observations have been recorded upon 
 this point, the majority of the observations being made in the fall of 
 1902. Considering the temperatures prevailing at the four periods 
 studied, it appears that the range in development during the average 
 season at Victoria, Tex., has been included, and it seems probable 
 that from these temperatures as a basis the length of the egg stage 
 can be approximately determined for any season and for any locality 
 within the p resent area of infestation. 
 
 Table I. — Length of egg stage at certain periods. 
 
 Period of examination. 
 
 Number 
 of obser- 
 vations. 
 
 Mean 
 tempera- 
 ture for 
 period. 
 
 Average 
 effective 
 
 tempera- 
 ture" 
 
 Average 
 length of 
 
 egg 
 
 stage. 
 
 1902. 
 September 4-Oetoher 3.. 
 
 385 
 
 107 
 36 
 
 25 
 
 °F. 
 81 
 73 
 62 
 
 72. 5 
 
 of 
 
 38 
 L9 
 
 32. r> 
 
 Days. 
 
 2. 5 to 3 
 
 October 7-November 13 
 
 4 to 4. ■"> 
 
 November 27-Deceml>er 15 
 
 11 
 
 1JKK3. 
 May 27-Jnne 5 
 
 3..") to 4 
 
 
 
 Total 
 
 563 
 
 
 
 ''3. 4 to 4.1 
 
 
 
 
 
 «In considering the influence of temperature upon the weevils it has been assumed that, a- has 
 been found to be the case with other animals. 43° P. would be about the lowest temperature at 
 which the weevils would be active. Temperatures b 'low that point would have, therefore, no 
 influence upon their activity, while all above that point would. For this reason it is better to 
 speak of the "effective temperature."" meaning by that the number of degrees above 43° F. 
 Experiments made upon the influence of temperature \ipon the activity of weevils indicate 
 that this is very near the correct figure for this insect. 
 
 b Weighted average. 
 
 The extreme range observed in Table II in the length of this stage 
 is from two to fifteen days, while the average period for the whole 
 
22 
 
 number of observations is but three and six-tenths days. It is possi- 
 ble that the embryo can undergo an even greater retardation without 
 losing its vitality. 
 
 It may be noted here that drying of the square will also retard 
 embryonic development, but this condition does not occur in the field. 
 
 Table II. — Range in length, of egg stage. 
 
 Number 
 
 Length of 
 
 Number 
 
 Length of 
 
 of eggs. 
 
 egg stage. 
 
 of eggs. 
 
 egg stage. 
 
 
 Days. 
 
 
 Da i/s. 
 
 2 
 
 2 
 
 4 
 
 5 to 6 
 
 132 
 
 2 to 3 
 
 3 
 
 8 to 9 
 
 192 
 
 I 3 
 
 \ 2 to 4 
 
 5 
 
 10 to 11 
 
 15 
 
 10 to 12 
 
 42 
 
 " 3 to 4 
 
 4 
 
 10 to 13 
 
 ad 
 
 3 
 
 13 to 14 
 
 yo 
 
 1 3 to 5 
 
 2 
 
 13 to 15 
 
 40 
 
 4 to 5 
 
 
 
 13 
 
 / 5 
 
 \ 4 to 6 
 
 
 
 The length of the egg stage in bolls does not appear to differ greatly 
 from that in squares. 
 
 HATCHING. 
 
 While still within the egg the larva can be seen to work its mandi- 
 bles vigorously, and although a larva has never been seen in the act 
 of making the rupture which allows it to escape from the egg, it is 
 believed that the rupture is first started by the mandibles. The 
 larva3 do not seem to eat the membranes from which they have 
 escaped, but owing to the extreme delicacy of the skin it is almost 
 impossible to find any trace of it after the larva has left it and begun 
 feeding on the square. 
 
 HATCHING OF EGGS LAID EXTERNALLY. 
 
 It occasionally happens that females are unable to force an egg into 
 the puncture prepared to receive it and the egg is left on the outside 
 of the square or boll. Eggs so placed usually shrivel and dry up in a 
 short time. To test the possibility of a larva making its way into a 
 square from the outside, a number were protected from drying. Of 
 the 19 eggs tested, 6 hatched in from two to three days. In no case, 
 however, was the young larva able to make its way into the square 
 and it soon perished. The hatching of eggs laid externally is of no 
 importance, since the larvae must perish without doing any damage. 
 
 EATING OF EGGS DEPOSITED OUTSIDE. 
 
 The number of eggs left outside increases as the female becomes 
 weakened, and is especially noticeable shortly before her death. The 
 number of such eggs which may be found is greatly diminished by the 
 following peculiar habit, which was observed manj 7 times. Occasion- 
 ally it appeared that the puncture which the female had made for the 
 reception of an egg was too narrow to receive it, and after a prolonged 
 attempt to force it down the female would withdraw her ovipositor, 
 
28 
 
 leaving the egg .-n i he surface. She would i hen turn immediately and 
 devour the egg. After that, seeming conscious of her failure and 
 aware of tin* cause of it, she would proceed to find and enlarge some 
 what the cavity pre^ iously made. When this was completed she would 
 at tempi bo place another egg therein. The second attempt was usu 
 ally successful, but in one or two cases a female was seen to fail several 
 times, and iii more than half of these cases she ate the eggs, as has 
 been described. 
 
 PERCENTAGE OF EGGS THAT HATCH. 
 
 Definite records were not kept upon this point, but in the many 
 hundreds of eggs followed during these observations very few failed 
 to hatch, though some were mueli slower in embryonic development 
 than were others laid at the same lime and by the same female. It 
 is the writers' general impression thai less than 1 percent of the eggs 
 are infertile or fail to hatch. 
 
 THE LARVA. 
 DESCRIPTION. 
 
 The young larva, upon hatching from the egg, is a delicate, white, 
 legless grub of about 1 nun. (J- inch) in length. Kxcept for the 
 brown head and dark-brown mandibles, the young larva is atfirsl as 
 inconspicuous as the egg from which it came. As it feeds and grows 
 it continues to enlarge a place for itself in the square or boll until 
 the food supply has become exhausted or the vegetable tissues 
 are so changed as to be unsuitable for food. By this time, as a rule, 
 the interior of the square lias been almost entirely consumed and the 
 larval eastings are spread thickly over the walls of the cavity (PI. 
 Ill, fig. 15). This layer becomes firmly compacted by the frequent 
 turning of the larva as it nears the end of this stage. In the cell 
 thus formed occur the great changes from the legless grub to the fully 
 formed and perfect beetle (PI. I, figs. 7, 8, and 0). 
 
 Throughout this stage the bod}* of the larva preserves a vent rally 
 curved crescentic form (PL III, fig. 10). The color is while, modi- 
 fied somewhat by the dark color of the body contents, which show 
 through the thinner, almost transparent, portions of the body wall. 
 The dorsum is strongly wrinkled or corrugated, while the venter is 
 quite smooth. The ridges on the dorsum appear t ) be formed largel) T 
 of fat tissue. After becoming full-grown the larva ceases to feed, 
 the alimentary canal becomes emptied, and both the color and form 
 of the larva are slightly changed. The dark color disappears from 
 the interior and is replaced by a creamy tint from the transforming 
 tissues within. The ventral area becomes flattened, and the general 
 curve of the bod}Ms less marked. Swellings may be seen on the sides 
 of the thoracic region, and when these are very noticeable pupation 
 will soon take place. 
 
24 
 
 GROWTH. 
 
 It is impossible to follow the growth of an individual larva with- 
 out interfering so greatly with its normal conditions of life as to 
 make the observations unreliable. It seemed more accurate to meas- 
 ure larvae of approximately known ages. In these measurements the 
 natural curve of the body was not interfered with, but the measure- 
 ment taken across the tips of the body. In this way it was found 
 that in squares during the hot weather the length of the body 
 increases quite regularly by about 1 mm. a day. As it becomes 
 cooler the daily growth is less. In bolls which grow to maturity the 
 rate of growth is less and the length of the growing period is much 
 greater. Full-grown larvae vary in length from 5 to 10 mm. across 
 the tips of the curve. Larva^ of normal size in squares average from 
 G to 7 mm. The largest larva? are developed in bolls which grow to 
 maturity (PL III, fig. 10). 
 
 MOLTS. 
 
 To accommodate the rapid growth of the larva two or three molts 
 occur. The period of change from one instar or stage to the next is 
 so short that the chances of opening a square at just the right time 
 to observe the process are very small indeed. However, it has been 
 ascertained beyond question that two molts occur before the larva 
 reaches half its growth. The first occurs at about the second day 
 and the second at about the fourth day. Whether a third molt 
 occurs before rjupation can not be positively stated ; but having occa- 
 sionally found larva? which had certainly just molted, but which were 
 much larger than the usual size at the second molt, the writer is led 
 to suspect that three larval molts nmy 7 sometimes, though possibly 
 the} 7 do not always, occur. In bolls where the length of the larval 
 stage is often three or four times as great as that usually passed in 
 squares it seems almost certain that more than two larval molts occur 
 regularly. Counting only the first two molts which have been often 
 fuii nd, a third occurs at the time the larva pupates. 
 
 PROCESS OF MOLTING. 
 
 So little is known in regard to the molting of Curculionida? that the 
 process as observed is here recorded. In the cases observed, starting 
 at the neck, the skin split along the back, and was then pushed down- 
 ward and backward along the venter of the larva. The cast head 
 shield remained attached to the rest of the skin. 
 
 Immediately after casting the skin the head, as well as the rest of 
 the body of the larva, was of a pearly-white color. The tips of the 
 mandibles first became brown, and within a short time a yellowish- 
 brown color marked the entire integument of the head. 
 

 Plate II. 
 

 1' 
 
 Developmental Stages and Work of the Boll Weevil. 
 
 Fig. 13, Two boll weevils feeding on a square, natural size: fig. 14, egg isolated, 25 times natural 
 size; fig. 15, full-grown larva in square, natural size: iis. r . 16, full-grown larva isolated, natural 
 size: rig. 17. pupa, twice natural size: fig. 18, adult just transformed, natural size: fig.19, large 
 larvae in large boll, two-thirds natural size: fig. 20, pupal cell in boll, broken open, twice natural 
 
 size. (Original. | 
 
LENGTH « 'i LARVA] 
 
 Most of tho observations upon the larval stage wen etween 
 
 September I and Decemlter I lh.- temperatui Lingdur 
 
 mg the first hah' of September wan as high a^ [g ordinarily exp< 
 at Victoria during midsummer, and th< extremes of the 
 
 average season may bo considered as having • d. 
 
 The time of egg deposition waseasil) determined by exposing unln- 
 fested squares in breeding cages containing active females. The time 
 oi hatching of the larva could onlj' be found bj opening the sqti 
 and ii was bo ascertained. The newly hatched larva was then pi; 
 in a small <-a\ ii> mad.- bj lifting the covering on the Bide of a freshly 
 picked square and removing one or two of the immature anth< 
 The coverings were then replaced as carefully as possible. Another 
 disturbance was necessary to determine exactly the date of pupa- 
 tion. Observations made in this waj were checked by others using 
 larva' which were allowed to go from egg deposition to pupation 
 under natural conditions and without disturbance until the end of 
 the larval Btage was approximately reached, sine.' the sum of the 
 times found for the various stages agrees approximately with the 
 known length of the immature period in cases where nodisturban e 
 of normal conditions occurred, we may conclude that the periods 
 found for the Larval slap' were approximately correct. 
 
 Altogether 266 observations were recorded upon the Length of this 
 stage. The majority of the observations maybe include'd in three 
 groups, and when thus grouped they may be best considered in relation 
 to the effective tempera lure. Table III presents a brief summary of 
 these groups: 
 
 Table III. — General results as to length of larval stage in squares. 
 
 Period of examination. 
 
 1908. 
 
 September 6 to October 5 
 
 September 26 to October 21 
 
 November 11 to December 12 . _ 
 
 JSS. USSR ^;,r £-g 
 ■HST •ssr $3K --' 
 
 3 F. 
 78. 
 73. 
 
 >F. 
 35.7 
 30.6 
 
 195 
 15 
 15 
 
 Day 8. 
 
 6 to 9 
 
 7 to 12 
 20 to 30 
 
 During the heat of summer the larval stage requires approximately 
 one week. This time appears to hold so long as the mean average 
 temperature remains above 75° F. As the temperature falls below 
 that point there is a gradual increase in the length of this stage. The 
 average total effective temperature required during hot weather by 
 the larval stage is not far from 280° F. As development becomes 
 retarded by colder weather the average total effective temperature 
 required to complete it is much greater. 
 
 These facts may be expressed in general by statin-- thai during the 
 hottest summer weather the length of this stage Is somewhat Less than 
 
26 
 
 oik- week. Development becomes slower as the temperature falls, 
 but does not cease altogether so long as cotton can live. Even frosts 
 do not destroy larvae in the squares and bolls, and these may finish 
 development during warmer weather after the frost has taken place. 
 The length of the larval stage in bolls is as a rule much greater. 
 If the boll falls when small the increase is slight, but if an infested 
 boll grows on to maturity the larval stage more than any other is much 
 extended. Special observations upon the larval stage in bolls have 
 not been made, but reckoning from the known length of the whole 
 developmental period in maturing bolls we may conclude that the 
 Larval stage can not be less than six or seven weeks. 
 
 PUPAL CELLS IN BOLLS. 
 
 As the boll approaches maturity, the full-growu larva ceases to feed 
 upon the drying and hardening tissues of seed and fiber. Its excre- 
 ment, more or less mixed with lint, becomes firmly compacted, and in 
 the drying which occurs the mass forms a cell of considerable firm- 
 ness, within which pupation and the subsequent transformation to 
 the adult take place (PI. Ill, fig. 20). These pupal cells frequently 
 include a portion of the hull of a seed, but the writer has never found 
 a large larva or a pupa entirety inclosed within a single cotton seed. 
 The cells described are shorter and thicker than seeds, but in general 
 appearance there is considerable resemblance between them (PL XI, 
 fig. 4L). Doubtless these cells have misled some into the statement 
 that they have found weevils in cotton seeds. 
 
 PUPATION. 
 
 The formation of the adult appendages has gone a good way before 
 the last larval skin is cast. The wing pads appear to be nearly half 
 their ultimate size. The formation of the legs is also distinctly marked, 
 and the old head shield appears to be pushed down upon the ventral 
 side of the thorax by the gradual elongation of the forming proboscis. 
 Finally the tension becomes so great that the tightly stretched skin is 
 ruptured over the vertex of the head, and it is then gradually cast off, 
 revealing the delicate white pupa. The cast skin frequentlj' remains 
 for some time attached to the tip of the abdomen. 
 
 THE PUPA. 
 
 When this stage is first entered the insect is a very delicate object 
 both in appearance and in reality. Its color is either pearly white 
 or cream. The sheaths for the adult appendages are fully formed at 
 the beginning of the stage and no subsequent changes are apparent 
 except in color (PL I, figs. 5 and 6). The eyes first become black, 
 then the proboscis, elytra, and femora become brownish and darker 
 than the other parts (PL III, fig. 17). 
 
29 i 
 
 The final molt requires about thirt} minutes. The skin splits open 
 over the front of the head and slips down along the proboscis and 
 hack over the prothorax. The skin clings to the antennae and the tip 
 of the proboscis i ill after the dorsum has been uncovered and the legs 
 kicked free. Then by violently pulling upon the skin with the fore 
 legs first the tip of tli<' snout and then the antennas are freed, and 
 finally the shrunken and crumpled old skin is kicked off the tip of 
 i he abdomen by the hind Legs. 
 
 LKNGTB OF PUPAL STAGE. 
 
 The length of this stage is more easily determined than thai of any 
 other. It seemed to make Little difference in the time whether the 
 pupa' were allowed to remain in the squares or removed therefrom. 
 Considerable variation in the Length of this stage exists among indi- 
 viduals of the same generation and even between offspring of the 
 same female and from eggs laid on the same day. The period of 
 investigation ranged from July to December, so thai the extremes of 
 the season are included. Altogether over 450 observations were made 
 upon the Length of this stage. Nearly all of these are included in 
 Table IV, which shows a summary of the results. 
 
 Table IV. — Tabular arrangement of observations upon the length of pupal stage 
 
 in squares. 
 
 K* W ttsr tefe 
 
 vat!,,,.'. °«£^ ,'f "4,. tempera-ltompBr*. 
 
 Period <>t' examination. 
 
 Average Total 
 
 iper 
 tnre. 
 
 tare. 
 
 1902. 
 
 July 6 to 31 -. 161 
 
 September 16 to October 3 81 
 
 September 24 to October 28 lf>7 
 
 November 2 to 13 I 2S) 
 
 December 2 to 29 4 
 
 1></I/S. 
 
 2 to 5 
 
 3 to 7 
 
 4 to 8 
 
 5 to 6 
 10 to 16 
 
 J>(ll/s. 
 
 3.5 
 
 5. 2 
 6.0 
 5.6 
 
 14.5 
 
 ° F. 
 39. 65 
 
 36.05 
 
 31.1 
 26.2 
 18.55 
 
 138.8 
 187.5 
 186. 1 
 1 40. 7 
 269.0 
 
 It should be noted in connection with Table IV that the observa- 
 tions made in November were during a period of rather warm weal her 
 and that the temperature records for that time are incomplete. It is 
 likely thai the average effective temperature given for that period 
 might he different were the records complete. 
 
 The average length of this period during hot weather is from three 
 to four days, and the period increases as the cool fall weather 
 approaches to a maximum of about fifteen days. 
 
 A comparison of Tables I, III, and IV shows that the decrease in 
 temperature affects each stage in very nearly the same proportion. 
 In each case the maximum recorded length of any stage is about four 
 times its minimum, and the great retardation in each ease occurs 
 somewhere between 60° and 70° F. of mean average temperature, or 
 17° to 27° F. of effective temperature. Even greater retardation 
 occurs during the winter season. 
 
28 
 
 The Length of the pupal stage in large bolls has not been deter- 
 mined. It appears to be Longer than in squares, but it certainly can 
 not occupy the same proportional part of the entire developmental 
 period that it does in squares. 
 
 EFFECT OF BURYING SQUARES UPON PUPATION AND THE ESCAPE OF 
 
 ADULTS. 
 
 The experiments made upon this point were designed to ascertain 
 the value, if any, in the plowing under of squares as a means of 
 destroying the larvae and pupa? infesting them. But few experiments 
 seemed necessary to demonstrate the futility of this operation alone 
 as a means of controlling the weevil. 
 
 Squares which were known to be infested with about half-grown 
 larva* were placed in glass jars and covered with several inches of 
 quite dry and fairly well pulverized earth. When examination was 
 made it was found that pupation had taken place normalh 7 while the 
 squares were buried under from 2 to 5 inches of dirt. In no case 
 was pupation prevented, though a few weevils did not leave the 
 squares after having become adult. Altogether about 100 squares 
 were thus buried, and from them over 75 weevils emerged. 
 
 In a portion of the preceding tests careful examination was made 
 to ascertain how far toward the surface the newly emerged weevils 
 had succeeded in getting before they perished. It should be noted 
 that these weevils had never fed, and they would have, therefore, less 
 strength and endurance than such fully hardened adults as might be 
 buried in the ordinary processes of field cultivation. Furthermore, 
 the soil used was of finer texture and more compactly settled than it 
 would be in the field. Twenty-seven weevils were found in this exam- 
 ination, their location varying from the bottom of the jar to their 
 having escaped through 1 inches of soil. A weighted average shows, 
 however, that each weevil had made its way upward through 2 inches 
 of dirt. AVe may infer, therefore, that had these squares been buried 
 under less than 2 inches of fairly well pulverized earth, as would be 
 the case from field cultivation, but a small percentage of them would 
 have failed to make their way out. As it Avas, full}' three-fourths of 
 those leaving the squares made their way out through more than 2 
 inches of dirt. 
 
 In 1896 Mr. C. L. Marlatt noted that "the weevils can escape from 
 loose soil when buried to a depth of 3 inches, but when artificially 
 embedded 8 inches in moist soil they are unable to extricate them- 
 selves, as shown by test experiment." Quite extensive experiments 
 are now being made at Victoria to test the ability of the fully fed 
 adult weevils to escape after being buried at various depths and in soil 
 containing various percentages of water. That the moisture content 
 exerts a great influence upon the texture of the soil is especially 
 noticeable in the black bottom lands of the Texas cotton belt. While 
 
2 1 1 
 
 the results of these experiments ma} furnish reasons for changing our 
 conclusions upon tins point, ili«' present indication is that the bene 
 iici.il effect of thorough cultivation Lies in th<- direct influence which 
 that practice exerts upon the steady and rapid growth of the cotton, 
 thus favoring the production <>f squares, 1 1 1 « * setting of bolls, and the 
 early maturity of the crop rather than in the direct destruction of the 
 weevils by burying them either while in the squares or after the} liave 
 become adult. 
 
 THE ADULT. 
 BEFORE EMERGENCE. 
 
 Immediately after its transformation from the pupa the adult is 
 very Light in color and comparatively soft and helpless. The probos- 
 cis is darkest in color, being of a yellowish brown; tin 1 pronotum, 
 tibiae, and tips of the elyt ra come next in depth of coloring. The ely- 
 tra are pale yellowish, as are also the femora. 'Die month parts, claws, 
 and the teeth upon the inner side of the fore femora are nearly black. 
 The body is soft and the young adult is unable to travel (PL III, 
 fig. 18), consequently this period is passed where pupation occurs. 
 Usually two or more days are required to attain the normal coloring 
 and the necessary degree of hardness to enable the adult to make its 
 escape from the square or cell. 
 
 EMERGENCE. 
 
 The normal method of escape from squares and small bolls is by 
 cutting with its mandibles a hole just the size of the weevil's body 
 (PL IV, fig. 21). In large bolls the escape of the weevil is greatly 
 facilitated by the natural opening of the boll (PL IV, fig. 22). Often 
 the pupal cell is broken open by the spreading of the carpels, and 
 when this is the case the pupa, if it has not already transformed, 
 becomes exposed to the attack of enemies or, what is probably a more 
 serious menace, the danger of drying so as to seriously interfere with 
 a successful transformation. If the cell remains unbroken the weevil 
 always escapes by the path of least resistance, cutting its way through 
 as in the case of a square (PL IV, tig. 20). The material removed 
 does not appear to be eaten, but is rather cast aside and left within 
 the cell as a mass of line debris. 
 
 CHANGES AFTER EMERGENCE. 
 
 At the time of emergence the weevils are comparatively soft, and 
 they do not attain their final degree of hardness for some time after 
 they have begun to feed. If they never feed they never harden. 
 The color of the chitin is of an orange tinge at the time the weevils 
 leave the squares or bolls, but after exposure for some time it turns 
 to a dark chocolate browm. The development of the hair-like scales 
 is probably entirely checked by the drying of the chitin, but the 
 
30 
 
 darkening of the ground color makes the scales more apparent, and 
 thus gives the impression of further development after emergence has 
 taken place. 
 
 SIZE OF WEEVILS. 
 
 Size of boll weevils is an especially variable quantity, and, as usual, 
 varies almost directly in proportion to the abundance of the larval 
 food supply and the length of the period of larval development. The 
 ex1 remes arc so great that the smallest and largest weevils would be 
 thought by one not thoroughly familiar with them to be of entirely 
 different species. So far as dimensions may convey an idea of the 
 size, we may say that the weevils range from 3 to 8 mm. (I to J inch) 
 in length, including the proboscis extended, and from 1 to 3 mm. ( J z 
 to i inch) in breadth at the middle of the body. (See PL I, fig. 1.) 
 
 RELATION OF SIZE TO FOOD SUPPLY. 
 
 The smallest weevils are developed from squares which were very 
 small, and which, for some reason, either of plant condition or of 
 additional weevil injury, fell very soon after the ev;g was deposited. 
 The supply of food was not only small, but, owing to the immaturity 
 of the pollen sacs, its quality was also poor. Normally squares con- 
 tinue to grow for a week or more after eggs are deposited in them, and 
 such squares produce the weevils of average size and color. 
 
 The largest weevils are produced in bolls which grow to maturity. 
 In them the food supply is most abundant, and the period of larval 
 development is several times as long as it is in squares. Possibly 
 these differences in size may be better shown by a summary of 
 observations which were made upon the weight of adults. 
 
 WEIGHT OF ADULTS. 
 
 The weevils used in these experiments were bred to insure their 
 coming from the proper source. After emergence they were fed for 
 some time to bring them up to their normal weight. 
 
 Table V. — Summary of iceigJit of Weevils, 
 
 Source of weevils. 
 
 Bred from picked small squares . . 
 Bred from average fallen squares 
 Bred from large bolls 
 
 Total 
 
 Average weight per weevil, all sources 
 
 *»*«■ t33f. e 
 
 Grain. 
 
 ii. in:, 
 .231 
 .268 
 
 162 
 
 36.825 
 .227 
 
 It should be noted that these figures do not nearly represent the 
 weight of the extremes in size, but they do indicate the difference in 
 the average weevil of each class. 
 
 
61 
 
 COLOR. 
 
 Color is \ci\ often a variable character In Insects, and the l>oll 
 weevil presents considerable range in this respect. Whatever in flu 
 ences tin* size <»r the larva affects directly the Bize of the adult, ;in<l it 
 is noticeable that weevils of the same size are also, as a rule, closely 
 alike in color, in general, the smaller the size of the weevil the 
 darker brown is its color; the largesl weevils arc Lighl yellowish 
 brown. Between these two extremes arc the majority of average- 
 sized weevils, which are either of a gray-brown or dark yellow-brown 
 color. Weevils developing in iarge bolls, having an abundant food 
 supply and a developmental period averaging more than twice thai 
 of weevils in squares, arc Larger in size and more yellowish in color 
 than are those from squares. 
 
 The principal reason for the variation in color lies in the degree of 
 development of the minute hair-like scales, which are much more 
 prominently developed in the Large than in the small specimens, 
 although the color of old specimens is often changed by the rubbing 
 off pf the scales. The scales are yellow in color, while the ground 
 color of the chitin bearing them is a dark brown or reddish brown. 
 When the scales are but slightly developed, as seems to be the case 
 with small weevils produced from underfed larvae, the dark-brown 
 ground color is predominant, while in the case of large weevils pro- 
 duced from larva* having abundant food and a long period of devel- 
 opment the scales are largely produced and give the strong yellow 
 tone to the color which is characteristic of them. 
 
 The development of the scales appears to take place mostly after 
 the adult weevil has become quite dark in color but before it becomes 
 fully hardened. They seem, therefore, to be a sort of non-essential 
 aftergrowth which depends upon the surplus food supply remaining 
 after the development of the essential parts of the w r eevil structure. 
 
 SIZE AND COLOR NOT INDICATIVE OF SEX. 
 
 Eminent coleopterists have studied the boll weevil most carefully 
 with the purpose of discovering some external character by which the 
 sexes could be distinguished, but all have failed to find an}- reliable 
 points of distinction. The writer therefore does not hesitate to own 
 that he also has failed to find any reliable character for the distinc- 
 tion of the sexes. Many persons have the idea that the small dark 
 weevils are males and the larger and lighter-colored brownish-yellow 
 weevils are females. This idea is a mistaken one. In general it is 
 probably true that the males are slightly smaller than the females, 
 but judging from determinations of the sex of many hundreds of 
 weevils it may be stated positively that size and color are characters 
 which are related to food supply and length of the period of develop- 
 ment and are not indications of sex. The sexes seem to be about 
 equally represented among the smallest as well as the largest weevils. 
 
32 
 
 Characters commonly used to separate the sexes in the family Cur- 
 culionidaB are not distinctive in this species. As a rule the antennas 
 arc inserted nearer the tip of the snout in the male than in the female. 
 This character is variable among boll weevils; and though a large 
 number of accurate measurements might show that a slight difference 
 generally exists, it is too inconspicuous a character to be of general 
 use. With most species the top of the rostrum of the male is rougher 
 than is thai of the female. However it maybe with other species, 
 there is but little if any difference in this respect between the young 
 ad lilts of the boll weevil. As the individuals become older the greater 
 activity of the females serves to wear the roughness from the top of 
 the rostrum, and thus gradually, as a result of different habits, this 
 character becomes more distinctive. In less than half of the boll 
 weevils, however, is this character sufficiently noticeable to separate 
 the sexes. The terminal segment of the abdomen shows no external 
 difference in either sex, although in many weevils important charac- 
 ters are there found. 
 
 PROPORTIONS OF THE SEXES. 
 
 No reliable secondary sexual characters having as yet been discov- 
 ered, the certain determination of sex therefore rests solely upon the 
 primary characters, thus requiring a certain amount of dissection in 
 each case. Such determinations have been made upon large numbers 
 of weevils taken in the field and upon many bred in the laboratory at 
 various seasons of the year. The results are briefly summarized in 
 Table VI. 
 
 Table VI. — Proportions of the sexes. 
 
 Number 
 of males. 
 
 Number 
 of fe- 
 males. 
 
 Season of 1902, both, bred and from field 
 
 Hibernated weevils, 1902-3 - 
 
 First generation, 1903 
 
 Bred weevils, 1903 
 
 Field weevils, midsummer, 1903 
 
 Total 
 
 240 
 
 269 
 
 43 
 
 45 
 
 52 
 
 649 
 
 260 
 174 
 32 
 33 
 
 sS8 
 
 From these 1,207 determinations it appears that males are somewhat 
 more numerous than females, the percentage being nearly 54 of males 
 to 46 of females. It is noticeable, however, that the only season at 
 which a preponderance of males occurs is during late fall. If we 
 exclude the figures for hibernated weevils for a moment, we find that 
 the totals for the balance of the season are remarkably close for the 
 two sexes, being 380 males and 384 females. It seems safe to say, 
 therefore, that the sexes are practically equal in numbers except that 
 more males than females seem to be found among hibernating weevils. 
 It may be that the retardation of development due to approaching 
 

 Breeding Jar and Method of Escape of Adults from Squares and Bolls. 
 
 Fig. 21, Emergence hole made by weevil in square, natural size: fig. 22, weevil escaping nor- 
 mally from boll, two-thirds natural size: li.tr. 23, apparatus used in breeding weevils, one-fourth 
 natural size: fig. 24, larva destroying the ovary and preventing the bloom in large squares, 
 natural size: fig. 'J.'), leaf fed upon by weevils in confinement, one-half natural size: ii.ar. 26, 
 emergence hole of weevil from boll which never opened, two-thirds natural size. (Original.) 
 

 Fig. 27.— Larva in Square, Ovary Untouched, Natural Size. 'Original.'. 
 
 Fig. 28.— Large and Small Larv/e in Boll, Two-thirds Natural Size. 'Original.) 
 
88 
 
 cold weather favors the development <>f males. Nol only was there a 
 larger number of males than of females taken In December, L902, but 
 there were also more males than females taken in the field in the spring 
 of L903 among the hibernated weevils which lived through the winter. 
 According t<> the determinations made, 64 per cent <>f tin- 259 weevils 
 dying during the winter were males and 56 per ecu i of the weevils liv- 
 ing through the winter were also males, since ii appears thai females 
 require fertilization in the spring before they begin to deposit eggs, 
 the preponderance of males at that time acts as a provision to insure 
 i he propagat i<m <>f i he species. 
 
 LENGTH OF LIFE UPON SQUARES. 
 
 The observations made along this line may be divided into eight 
 groups, each dealing with some special food condition or class of 
 weevils. For the confinement of weevils in the Laboratory the most 
 satisfactory apparatus tried, both for convenience in handling and for 
 
 the maintenance of favorable conditions for the weevil, was made up 
 as follows: A 4 or 5 inch shallow earthen saucer, such as is used with 
 flowerpots, was tilled with soil, which was kept fairly moist. Over 
 tins was placed a fresh cotton leaf, which conserved the moisture from 
 the soil, but never became wet, and kept both weevils and squares 
 clean, besides facilitating the handling necessary to frequent renew r - 
 als of the food supply and the consequent transference of the weevils. 
 The rest of the cage was formed by an ordinary lantern globe cov- 
 ered at the top by cheese cloth held firmly in place by a rubber band. 
 With this apparatus weevils could be readily observed without dis- 
 turbing them, and food supplied was kept in good condition and could 
 be easily renewed, while there were no cracks to hide in or to allow 
 weevils to escape (PL IV, fig. 23). The moisture of the soil and 
 fresh leaf covers were renewed as needed. Clean squares were sup- 
 plied each day, and the actual number of egg and feeding punctures 
 recorded upon numbered slips kept with each cage. The sex of each 
 weevil was also determined and noted upon its death, thus giving an 
 accurate record of the number and sex of weevils responsible for the 
 punctures recorded. Most of the weevils used were bred, so that the 
 exact length of their lives is known. Length of life refers only to 
 adult life from the time of emergence from the square or boll to the 
 death of the weevil. Many weevils brought in from the field were 
 under observation in the laboratory for periods sufficiently long to 
 justifjr the inclusion of the results obtained from them with those of 
 weevils which were bred. Obviously the time these were under 
 observation does not represent their true length of life; therefore the 
 inclusion of both results renders the averages obtained the more con- 
 servative. 
 
 21739— No. 45—04 3 
 
34 
 
 Table VII. — Length of life of weevils upon squares. 
 
 Males. 
 
 Number. *™^° 
 
 Weevils placed in hibernation Dec. 15, 1902: living Apr. 15. 
 
 UXtt... 23 
 
 Hibernated weevils taken spring, 1903; estimated adult 
 
 Dec. 15, 1902 66 
 
 f OQ 
 
 Hibernated weevils, from time of feeding in 1903 %~ 
 
 First generation, bred | 30 
 
 Third generation, bred 18 
 
 Fifth generation, bred | • 9 
 
 Totals and weighted averages, including hibernation 
 
 period 146 
 
 Totals and weighted averages, npt including hibernation I 
 
 period 147 
 
 Entire length of life, hibernated weevils only J 89 
 
 180 
 223 
 
 151 
 
 71 
 212 
 
 Females. 
 
 Number. Avenge 
 
 111 
 
 112 
 67 
 
 171 
 
 220 
 
 148 
 
 64 
 
 210 
 
 Whether we include the time of hibernation or not, it appears from 
 the averages of 156 hibernated weevils that those which winter suc- 
 cessfully are longer lived than any following generation, as their 
 active life in spring averaged fully 80 days for males and 70 for 
 females. Probably the greater activity of the first generation may 
 account for their somewhat shorter life. The average active life 
 
 period for all generations is probably not far from 
 and 61 days for females. 
 
 1 davs for males 
 
 LENGTH OF LIFE ON BOLLS ALONE. 
 
 As weevils appear to feed freely on bolls in the field after the period 
 of maximum infestation has been reached (PI. I, fig. 10), these tests 
 were made to determine whether they might be able to live normally 
 with no other food. 
 
 A number of weevils were placed upon bolls as soon as they became 
 adult. Others which had first been fed upon squares were given bolls 
 after they had become hard and had shown themselves to be in a nor- 
 mally healthy condition. Of the total 37 weevils thus tested, 16 were 
 males and 21 were females. The males showed an average length of 
 life of 19.7 days, while the females survived for only 15.2 days. This 
 is a much shorter period than the normal length of life upon squares 
 for either sex. 
 
 LENGTH OF LIFE ON COTTON LEAVES ALONE. 
 
 To determine whether they could live upon the foliage of cotton 
 alone 69 newly transformed weevils were at the 1st of October, 1902, 
 placed upon fresh leaves, which were renewed at frequent intervals. 
 During the first three weeks 52 of these weevils (21 male and 31 
 female) died, leaving 17 alive and well; 11 of these were then returned 
 to squares and 6 continued upon the leaves. Of these 6, 3 lived to be 
 81 days old and were then intentionally killed for dissection. The 
 
35 
 
 average length of Life of those kept entirely upon leaven was over 30 
 days. These results show clearij the ability of main of the weevils 
 to live upon foliage alone in fields In which fall grazing ifl practiced 
 until ii becomes sufficiently cold for them to go into winter quarters 
 (see PL [V, Bg. 25). 
 
 LENGTH OF LIFE with SWEETENED WATEB \M> WITH MOLASSES. 
 
 So mnch has been said about the attraction of molasses for the 
 uir\ Ha thai tests were made with a cheap grade of molasses diluted 
 whli from 20 to 25 parts of water to see whether this solution really 
 served them as food. The weevils used were jusi adult and had taken 
 no other food. They fed quite readily upon the solution, remaining 
 quietly with their snouts in the water for from a few minutes to an 
 hour and a half at a time. The solution did not seem to draw them 
 from any distance, but as soon as a Aveevil came to it it would stop to 
 drink. Feeding or drinking- took place daily or often er until the 
 death of the weevils. The average length of life for the 12 weevils 
 used was a little less than (5 days. 
 
 As weevils without food but with water lived an average of 5£ 
 days, the conclusion is that a solution of molasses 1 to water 25 parts 
 does not serve the weevil as food, since it does not noticeably prolong 
 life. 
 
 Six weevils just emerged kept upon undiluted molasses showed a 
 greater length of life, these dying at an average age of 1H days. 
 
 LENGTH OF LIFE WITHOUT FOOD, BUT WITH WATER. 
 
 These observations were made during August as a check upon those 
 without water. The 8 weevils used were just adult and had never 
 fed. Each weevil drank for one or two minutes at least once each 
 day so long as it lived. All died at nearly the same time, having 
 lived for an average of about 5^ days. As those without water lived 
 an average of 5 days, it appears that access to water in the absence 
 of food does not materially increase the length of life of the starving 
 weevils. 
 
 LENGTH OF LIFE WITHOUT FOOD OR WATER. 
 
 Three series of observations were made along this line. In the first 
 the weevils used were taken immediately after emergence and never 
 allowed to feed. Fifty weevils were tested in this way during July 
 and August and showed an average length of life of 5 days from the 
 date of emergence. A few lived as long as 8 or 9 days. These never 
 acquired as dark a color nor as great a degree of hardness as is normal. 
 
 In the second series the 15 weevils used were 7 weeks old and full- 
 fed at the time of beginning the test. These showed an average length 
 of life of slightly over 6 days, the range being from 5 to 9 days. These 
 weevils were tested during the latter half of November, and the late- 
 
36 
 
 aesfi of the Reason, together with the fall-fed condition of the weevils, 
 seemed to promise a considerably Longer period than 6 days. 
 
 In the third series the L8 weevils used were 1 month old and full* 
 fed at the beginning of the test in the middle of November. The con- 
 ditions in this series were as in the series preceding, with the excep- 
 tion that an abundance of two species of grass taken from cotton 
 fields was included. These weevils showed an average length of life 
 of nearly 1\ days, ranging from 3 to 10 days. The weevils made no 
 effort to feed upon the grass, so the slightly longer life period must 
 be due to other causes. 
 
 CANNIBALISM. 
 
 It is hardly proper to speak of cannibalism as a food habit of the 
 boll weevil, but the facts observed may well be recorded here. Under 
 the impulse of extreme hunger weevils have several times showed a 
 slight cannibalistic tendency. 
 
 Seven beetles were confined in a pill box without food. On the 
 third day 6 only Avere alive. Of the seventh only the hardest chitin- 
 ized parts (head, proboscis, pronotum, legs, and elytra) remained, the 
 softer parts having been eaten by the survivors. 
 
 In another box containing 12 adults the leaf supplied for food was 
 insufficient, and on the fourth day 8 were dead, 4 were partly eaten, 
 and others had lost one or more legs each. 
 
 In another case a few young adults and a number of squares con- 
 taining pupae were placed in a box together with a few fresh squares 
 to serve as food for the adults. When the box was opened after a 
 number of days, one "reddish-brown" adult was found having its 
 elytra eaten through and most of its abdomen devoured. In spite of 
 tins mutilation the victim was still alive and kicking slowly. The 
 squares were still fresh and fit for food, so that this is really the clear- 
 est case of cannibalism observed. 
 
 Frequent!}" more than one larva hatches in a square, and when this 
 is the case a struggle between them is almost certain to take place 
 before they become full grown. Many cases have been observed in 
 which squares contained one living and one or more smaller dead 
 larva?, while in a few cases the actual death struggle was observed. 
 
 HABITS. 
 
 Among the habits of any insect of economic importance, the first 
 for careful study are those relating to its food, and secondly those 
 connected with its propagation. The study of the life history of the 
 boll weevil has revealed no especially vulnerable point, but rather the 
 important fact that in all its stages it is better protected against the 
 attacks of enemies and the ordinarily effective remedies recommended 
 by the economic entomologist than any other insect which has ever 
 threatened the production of any of the great staple crops of this 
 
87 
 
 count i\ . Naturally, then, we must needs turn to a Btudj of the habits 
 of the pest to point 1 1 1 « * waj i<» means i>\ which either ii may be itself 
 destroyed or its great destructiveness prevented, 
 
 FOOD HABITS. 
 L \K\AL. 
 
 1 1 is plainly the intention of the mother weevil to deposit her egg so 
 that t li«' larva upon hatching will find itself surrounded by an abun- 
 dance of favorable food. In thegreal majority of cases this food con- 
 sists principally of immature pollen. This is the lirst food of the larva 
 which develops in a square, and it must be both delicate and nutritious. 
 Often a Larva will eat its way entirely around a square in its pursuit 
 of this food. In most eases the larva is about half grown before it 
 feeds to any extent upon the other portions of the square. It may 
 then take the pistil and the central portion of the ovary, scooping out 
 a smoothly rounded cavity for the accommodation of its rapidly 
 increasing bulk (PL I, fig. 7; PI. Ill, fig. 15; PI. IV, fig. 24). So 
 rapidly does the larva feed and grow that in rather less than a week 
 it has devoured two or three times the bulk of its own body when fully 
 grown. It sometimes happens that the square is large when the egg 
 is deposited therein, and the bloom begins to open before the injury 
 by the larva is sufficient to arrest its development. In many cases of 
 this kind the larva works its way up into the corolla and falls with it, 
 leaving the young boll quite untouched (PL V, fig. 27). Occasionally 
 the flower opens and fertilization is accomplished before an}- injury 
 is done the pistil, and in rare cases a perfect boll results from a truly 
 infested square. Sometimes the larva when small works its way down 
 into the ovary before the bloom falls, and in such cases the boll falls 
 as would a square. 
 
 In large bolls the larva? feed principally upon seed and to some extent 
 upon immature fiber. A larva will usually destroy but one lock in a 
 boll, though two are sometimes injured (PL V, tig. 28). 
 
 ADULT. 
 
 Before escaping from the square the adult empties its alimentary 
 canal of the white material remaining therein after the transforma- 
 tion. The material removed in making an exit from the cell is not 
 used as food, but is cast aside. Weevils are ready to begin feeding- 
 very soon after they escape from the squares or bolls in which the 
 previous stages have been passed. For several days thereafter both 
 sexes feed almost continuously and seem to have no other purpose in 
 life. They will take squares, bolls, or leaves, but they much prefer 
 the squares, and when squares are present in the field it is probable 
 that leaves are seldom touched. As has been shown, however, weevils 
 can live for a long time upon leaves alone when squares and bolls are 
 
38 
 
 wanting. Bolls are only slightly attacked so long as there is an 
 abundance of clean squares. 
 
 The method of feeding is alike in both sexes. The mouth-parts 
 are very flexibly attached at the tip of the snout (fig. 2) and are 
 capable of a wide range of movement. The head fits smoothly into 
 the prothorax like the ball into a socket joint and is capable of a con- 
 siderable angle of rotation. The proboscis itself is used as a lever in 
 prying and helps to enlarge the puncture through the floral envelopes 
 especially. Feeding is accomplished by a combination of movements. 
 The sharply toothed mandibles serve to cut and tear, while the rota- 
 tion of the head gives the cutting parts an auger-like action. The 
 forelegs especially take a very firm hold upon the square and help 
 to bring a strong pressure to bear upon the proboscis during certain 
 portions of the excavating process. The outer layer of the square, 
 the calyx of the flower, is naturally the toughest portion that they 
 have to penetrate, and only enough is here 
 removed to admit the snout. After that is 
 pierced the puncture proceeds quite rapidly, 
 combinations of chiseling, boring, and prying 
 movements being used. While the material 
 removed from the cavity is used for food, the 
 bulk of the feeding is upon the tender, closely 
 compacted, and highly nutritious anthers or 
 pollen sacs of the square. When these are 
 reached the cavity is enlarged, and as much is 
 eaten as the weevil can reach. The form of 
 the entire puncture becomes finally like that 
 of a miniature flask. 
 
 Only after weevils have fed considerably do 
 sexual differences in feeding habits begin to 
 appear (PL III, fig. 13), the females puncturing mainly the base and 
 the males the tip of the square. 
 
 Feeding punctures are much larger and deeper than are those made 
 especially for the reception of the eggs (PI. I, fig. 3); more material 
 is removed from the inside of the square or boll and the opening to 
 the cavity is never intentionally closed. Feeding punctures are most 
 frequently made through the thinner portion of the corolla not covered 
 by the calyx. The exposed tissue around the cavity quickly dries 
 and turns brown from the starting of decay. As a number of these 
 large cavities are often formed in one square (PL VI, fig. 29), the 
 injury becomes so great as to cause the square to flare immediately, 
 often before the weevil has ceased to feed upon it. Squares so 
 severely injured fall in a very short time. The injury caused by a 
 single feeding puncture is often overcome by the square and its nor- 
 mal course of development is continued. When feeding punctures 
 are made in squares which are nearly ready to bloom, the injury com- 
 
 Fig. 2.— Mexican cotton boll 
 weevil, head showing ros- 
 trum with antennae near 
 middle and mandibles 
 at end— much enlarged 
 (original). 
 
89 
 
 moiih produces ft distorted bloom (PI. VI, fig, 30) and in \<-i\ severe 
 eases the boll will drop soon after setting. 
 
 Alter the females begin t<> oviposit their feeding habits become 
 quite different from those of the males. Up t«> iliis time i»<>tli s.-\.n 
 move I >ii i little, makings number of punctures In ;i single square; but 
 from this point we must consider the feeding habits of the sexes sep 
 arately. 
 
 \l U.K. 
 
 Studies of the feeding habits of males have been made both in the 
 laboratory and <>ut of doors. In the laboratory 65 males were under 
 observation during a total period of 2,492 weevil-days. a During this 
 period 2,185 squares were supplied them and they made 5,617 feeding 
 punet ures in l ,582 of these squares. A Little calculat ion shows that they 
 averaged to make &j feeding punctures In each square, at the rate of 2j 
 punctures a weevil each day. These observations were in most cases 
 made during the latter part of each weevil's life. During the first few 
 days 1 hey have often been found to make from 6 to 9 punctures a day. 
 A general average of 3 feeding punctures a day in the laboratory 
 would seem to be near the actual figures during the warm weather. 
 
 As each male while under observation attacked only about -2 
 squares every 3 days, the destruetiveness of males seems compara- 
 tively slight. 
 
 Five males were followed upon plants under a field cage for a total 
 period of 145 weevil-days. During this period they attacked 08 
 squares, making therein a total of 177 feeding punctures. This 
 means an average of 2A> punctures per square and an average of 1.2 
 punctures per male per day, making the number of squares attacked 
 by each male less than 1 ever}' 2 days. These outdoor observations 
 indicate that the laboratory results, small though they appear, are 
 yet higher than the actual field numbers. Whether in or out of 
 doors, the activity of feeding decreases as the male grows older. 
 
 .Males choose to puncture more often than do females through the 
 tip portion of the square not covered by the calyx. The yellow or 
 orange colored excrement is abundant, and owing to the somewhat 
 sedentary habits of the males it accumulates often in quite large 
 masses. 
 
 FEMALE. 
 
 After they begin to oviposit females seem generally to feed less 
 upon one square or in one puncture than they do previous to that 
 time. They obtain quite a considerable portion of their food from 
 the excavations which they make for the deposition of their eggs, and 
 as they show a strong inclination to oviposit only in clean or pre- 
 viously uninfested squares, their wandering in search of Buch squares 
 
 fl The term "weevil-day" is used for convenience to designate the product of 
 the two factors: number of weevils multiplied by the number of days. 
 
40 
 
 keeps their punctures scattered so long as plenty of clean squares can 
 be found. When clean squares become scarce, the normal inclination 
 can not be followed out, and the number of punctures made in one 
 square will be greatly increased. Most of the special feeding punc- 
 tures of females appear to be made either in the early morning or 
 near sundown, the middle and warmest portion of the day being 
 given mainly to egg deposition. The total amount of feeding done is 
 really very large, as is shown by a few figures. 
 
 MALES AND FEMALES TOGETHER. 
 
 During the season of 1003 a large number of weevils was kept in 
 the laboratory for special study, but as several weevils were confined 
 in each cage, the work of the sexes can not be positively separated. 
 A comparison of the results can best be made by means of a tabular 
 arrangement of the figures. 
 
 Table VIII. — Number of punctures per weevilper day. 
 
 
 Number 
 of males. 
 
 Number 
 of fe- 
 males. 
 
 Total. 
 
 Average. 
 
 Characterization of 
 lot. 
 
 Weevil 
 days. 
 
 Feeding 
 punc- 
 tures. 
 
 Egg 
 punc- 
 tures. 
 
 Feeding 
 
 punc- 
 tures per 
 weevil 
 day. 
 
 Egg 
 
 punc- Period of 
 tures per observa- 
 female tion. 
 day. ! 
 
 Hibernated weevils 
 in laboratory. - 
 
 Hibernated females 
 in field cage 
 
 55 
 
 54 
 4 
 
 27 
 5 
 
 4,938 
 93 
 
 3,258 
 
 7(i 
 
 2,492 
 
 17,406 
 
 284 
 
 16,487 
 263 
 
 5,617 
 
 5,702 
 489 
 
 3,565 
 435 
 
 3.5+ 
 3.0+ 
 
 5.0+ 
 3.8- 
 
 2.3- 
 
 2.3+ 
 5.3- 
 
 2.4- 
 
 6.2+ 
 
 Days. 
 45.3+ 
 
 23.3- 
 
 Weevils of first gen- 
 eration in labora- 
 tory 
 
 31 
 
 56.2— 
 
 Females, first gener- 
 
 14.0 
 
 Males only, labora- 
 torv. summer of 
 1903. 
 
 65 
 
 3S.3+ 
 
 
 
 
 
 
 Total.... 
 
 151 
 
 90 
 
 10,851 
 
 40,057 
 
 10,191 
 
 
 
 
 
 
 
 
 FEEDING OF HIBERNATED AVEEVILS ON EARLY COTTON. 
 
 During the period in which hibernated weevils were coming from 
 their winter quarters and seeking their first food, frequent examina- 
 tions Avere made in fields where the cotton was most advanced to learn 
 the first-food habits of such weevils. From statements made by pre- 
 vious investigators the writer is led to believe that the season of 1903 
 at Victoria was abnormal in respect to the small number of hiber- 
 nated weevils which w r ere to be found upon the young cotton in the 
 field. The most careful search failed to discover more than a very 
 few weevils, whereas at the same season in some years hibernated 
 weevils have been picked in large numbers from the young cotton 
 growing in the infested territory. 
 
 Whether they be few or many, however, makes no difference in 
 the feeding habits of the hibernated beetles. The stage of the cotton 
 determines largely the nature of the food habits at this time. Owing 
 
II 
 
 to the extremely wet winter and the very late — i » i i 1 1 ^r * » r 1903, little 
 coi i nn could be planted until the latter pari of March or i he Aral pari 
 of April. In such a season as this, therefore, cotton musl be nmall 
 at the time of the emergence <»f the wreevils from hibernation, and 
 sometime musl elapse before the formation of the flrsl squares fur- 
 nishes the weevils with t heir normal food supply. During this inter- 
 val the weevil gets mosl of its food from the tender, rapidly growing 
 terminal portion of the young plants, as several observers have noted. 
 The central bud, young leaves, or the tender stems are attacked ami 
 upon these the weevils easily subsist until squares are developed, aftei 
 which they confine their injury to them. 
 
 The earliesl plants in afield seem to attracl most of the weevils, 
 and where Beppa a plants occur they serve as excellent traps i<> draw 
 the first attacks. Thus, in the spring of L895Mr. E. A. Schwarz found 
 the first emerged hibernated weevils working upon seppa plants which 
 had sprung from 2-year-old roots. These plants seem to starl earlier 
 and grow more vigorously than do those from Beed and are therefore 
 doubly tempting to the hungry weevils. 
 
 In L896 Mr. Marlatl noted "the eating in the field on volunteer cot- 
 ton is practically confined to the young expanding leases at the bud 
 and to the tender petioles or stems of this portion of the plant." 
 
 In the spring of 1903, in one field of comparatively early eotton, 2 
 (>]• 3 acres in extent, the writer found, between April 24 and May 11, 
 23 weevils working on the buds and tender leaves of seppa plants 
 before a single weevil was found upon the young planted eotton bas- 
 ing from 4 to s leaves. 
 
 If, however, the cotton should be further advanced at the time the 
 weevils appear, they would then go at once to the squares. Even 
 then they prefer to attack the most advanced plants, which have a 
 number of nearly grown squares, rather than the smaller plants which 
 are but just beginning to square. Seppa plants, where such exist, 
 come in, therefore, for a large part of the firsl at tack of the hibernated 
 weevils. This fact is well shown by observations made by .Mr. A. \. 
 Caudell, of the Division of Entomology, at Victoria, at about the 
 middle of June, L902. In an examination of 100 seppa plants growing 
 in a planted, held he found that fully half of the squares upon those 
 plants were then infested. The planted cotton was just beginning to 
 form squares, and was but slightly injured at thai time. 
 
 INCREASE IX LEAF AREA OF COTTON. 
 
 The advisability of making observations upon this point was sug- 
 gested by the attempts made to poison hibernated weevils by spraying 
 early eotton with an arsenical insecticide. As the weevils fed so 
 
 " " Seppa *' is the term used by the Mexican residents of South Texas to differ- 
 entiate the cotton plants springing from the roots of the previous year from those 
 strictly "volunteer.'* springing from accidentally scattered seeds. 
 
42 
 
 exclusively in the most recently unfolded growing portions at the tips 
 of the stems, it was evident that the rapidity of increase in the leaf 
 area would at least indicate the frequency with which spraying would 
 have to be repeated in order to keep in a poisoned condition the very 
 limited portion upon which the weevils fed. 
 
 Although the observations were made after midsummer, the plants 
 used were of the right size to indicate the points desired. Two scries, 
 each including five average plants, were selected. 
 
 The plants used in Series I had 8 leaves at the time of the first 
 observation. Those used in Series II were older and averaged about 
 30 leaves each. The leaves borne upon the main stem were classed 
 as primary and those from side branches as secondary leaves. Upon 
 the date of each of the 5 observations made, the number of leaves in 
 each class was ascertained, an average leaf in each class was quite 
 accurately measured, and the total product of numbers and area thus 
 found was considered as the approximate leaf area of the plant. The 
 error has been reduced as much as possible by taking an average of 
 the 5 plants in each series as representing a typical plant, and it is 
 with these results that comparisons have been made. 
 
 Table IX. — Estimated increase in leaf area of cotton, averages of five plants. 
 
 Primary leaves. 
 
 Date of examination. 
 
 Average 
 number 
 
 {)er 
 ant. 
 
 Average 
 area, 
 plant. 
 
 Series I: 
 
 August 30 
 
 September 13 
 September 25 
 
 October 6 
 
 October 17 
 
 Series II: 
 
 August 30 
 
 September 13 
 September 25 
 
 October 6 
 
 October 17 
 
 1902. 
 
 8.0 
 
 11.0 
 13.2 
 
 7.8 
 8.4 
 
 9.6 
 10.0 
 
 Sq. in. 
 64.0 
 
 Percent- 
 age of 
 
 daily in- 
 crease. 
 
 Secondary leaves. 
 
 Average Avpra „ p 
 number A ™^ e 
 
 pPant. P**. 
 
 136.8 
 231.6 
 309.6 
 376.6 
 
 177.2 
 
 8.0 
 5.4 
 3.0 
 2.0 
 
 229.2 
 241.6 
 214.8 
 216.8 
 
 2.6 
 .04 
 «-1.0 
 
 0.0 
 
 8.0 
 
 16.6 
 
 22.6 
 
 31.0 
 
 21.6 
 
 24.8 
 42.4 
 
 Sq. 
 
 41.2 
 187.4 
 347.X 
 522.4 
 
 266.8 
 341.4 
 514.0 
 619.2 
 808.8 
 
 Percent- 
 age of 
 
 daily in- 
 crease. 
 
 30.0 
 7.8 
 4.6 
 
 2.0 
 3.6 
 1.8 
 2.1 
 
 « Decrease of 1 per cent due to falling of old primary leaves. 
 
 Several facts are evident from an examination of this table. After 
 the plant has acquired about eight primary leaves the formation of 
 branches and of secondary leaves began, thereby multiptying the 
 number of growing points. From this time on the greater part of the 
 increase in leaf area took place in the secondary leaves. By far 
 the most rapid period of leaf growth occurred at about the time when 
 squares first began to form. In Series I the average total leaf area 
 practicalry doubled every ten days through the seven weeks under 
 observation. In Series II the plants were older to start with, and it 
 required about forty days to double the leaf area. 
 
 Everyone now concedes that it is useless to attempt the spraying 
 of full-grown cotton such as is represented in Series II. The extreme 
 
i:; 
 
 rapidity of Increase In the foliage area shown in the ftrel pari of 
 Scries I shows that spraying must i»< i repeated everj week or ten days 
 if even one-half of 1 1 1 « * entire Leaf area is t<> be kept poisoned. When 
 in connection with the Large per oenl of daily Increase we consider 
 how much of that percentage is being unfolded at tin- verj tip of the 
 stem; thai upon that Limited tip area alone will the weevil feed before 
 the formation of Bqnares; that after the formation of squares it 
 appears t<> be absolutely impossible to poison the weevil's food sup- 
 ply, and also that the irregular emergence of the weevils from hiber- 
 nation may extend through several weeks, it at once becomes evident 
 that Bpraying early cotton for hibernated weevils is almost as imprac- 
 ticable as the spraying of older cotton is now acknowledged t<> l>c 
 
 EFFECTS OF FEEDING UPON SQUARES AND BOLLS. 
 
 Prom numerous large, open, feeding punctures a square becomes 
 
 so severely injured that it Hares very quickly, often within 24 hours. 
 .Males usually make the Largest punctures, and always leave them open 
 while they remain for a day or more working upon the same square. 
 It lias been often found that squares thus injured by a male will Hare 
 before the weevil leaves it. The time of flaring depends upon the 
 degree of injury relative to the size of the square. Thus, small squares 
 receiving only a single large feeding puncture in the evening are found 
 widely flared in the morning. On the other hand, large squares which 
 are within a few days of the time of their blooming may receive a 
 number of punctures without showing any noticeable flaring. Fre- 
 quently a square which has flared widely will be found later to have 
 closed again and to have formed a distorted bloom (PI. VI, fig. 30; PI. 
 VII, fig. 31), and occasionally such squares develop into normal bolls. 
 In squares of medium size a single feeding puncture does not usually 
 destroy the square. The destruction of a square by feeding results 
 either from drying, decay, or a softened, pulpy condition of the 
 interior which is the consequence of the weevil injury. 
 
 Bolls are quite largely fed upon after infestation has reached its 
 height. Small and tender bolls are often thoroughly riddled by the 
 numerous punctures (PL VII, fig. 32). Small bolls so severely injured 
 fall within a short time. Larger bolls may receive more punctures 
 without being so severely injured. A comparison of the external 
 and internal effects in such cases is shown in PI. VIII, figs. 34, 35. 
 Abnormal woody growth takes the place of the normal development 
 of the fiber, and a softening and decay of the seeds often accompanies 
 this change. One or more locks may be destroyed while the remain- 
 der of the boll develops in perfect condition (PI. VII, fig. 33; PI. X, 
 fig. 38). 
 
 After the bolls become about half grown the effects of feeding are less 
 liable to cause the boll to fall (PI. I, fig. 10). The puncture becomes 
 closed by a free exudation of the sap and a subsequent woody growth, 
 
44 
 
 which forms frequently an excrescence the size of half a pea upon the 
 inner side of the carpel. An excrescence of this character usually 
 results from an egg puncture, and often from feeding punctures. 
 
 DESTRUCTIVE POWER BY FEEDING. 
 
 A glance at the figures in Table VIII (p. 40) is sufficient to show 
 the great destructive power of the Mexican cotton boll weevil. It 
 may be seen that both in the field and in the laboratory the weevils 
 of the first generation are more active in making punctures than are 
 the hibernated Aveevils. These generations overlap too far to attribute 
 this difference to the influence of a higher temperature alone, though 
 this factor will account for a large part of it. A comparison of the 
 figures for males alone with those for females alone or with those for 
 males and females together shows that it is very conservative to say 
 that males make less than half as many punctures as do females. By 
 the habit of distributing their punctures among a greater number of 
 squares the destructiveness of the females becomes at least five times 
 as great as that of the males. 
 
 This great capacity for destruction has been one of the most evident 
 points in the history of the spread of the weevil, and deeply impressed 
 the entomologists who first studied the insect in Texas. In 1895 Mr. 
 E. A. Schwarz, in writing of the work of the weevil at Beeville, said : 
 
 Each individual specimen possesses an enormous destructive power and is able 
 to destroy hundreds of squares, most of them by simply sticking its beak into 
 them for feeding purposes. 
 
 SUSCEPTIBILITY OF VARIOUS COTTONS. 
 
 An excellent opportunity for observations upon this point was 
 obtained upon the laboratory grounds at Victoria by growing within 
 a small area plants of several varieties of American Upland, Sea 
 Island, Egyptian (Mit Afifi), Peruvian, and Cuban cotton (Algodon 
 sylvestre). The Peruvian cotton made a remarkably large growth, 
 but put out no squares, so that it does not really enter into this com- 
 parison. The Mit Afifi seed was obtained through the courtesy of the 
 Bureau of Plant Industry of this Department from a field grown the 
 preceding season at San Antonio, Tex., in which circumstances led 
 some observers to the opinion that the variety was, to a certain extent, 
 immune. The observations at the laboratory were made by carefully 
 examining the plants, looking into each square, and removing every 
 weevil and infested square found. If there were any distasteful or 
 resistant cotton among these, it would surely be found in this way; 
 and if any variety were especially attractive to the weevils it would 
 be equally apparent. Infested squares being removed, the accident 
 of association or proximity would not determine the location of the 
 weevils found, but all might be considered as having come to the cot- 
 ton with equal opportunities to make their choice of food, and accord- 
 
i:. 
 
 i 1114,1 \ their location has been considered as indicating such choice. 
 The period <>f observation extends from June to November, <\<-<'|»i 
 
 w ii h tlir c uhan coiion, which was planted late and began to square 
 during the latter part of August. For the purpose of this comparison, 
 both the varieties and the several plots of the American cotton will be 
 considered together, as no evidence of preference was found among 
 them. 
 
 In making a comparison of the results three elements must be oon- 
 sidered for each variety of cotton : First , the number of plan is of cadi 
 variety ; second, the number of days during which each kind was 
 under observation; third, the total number of weevils found on each 
 class of cotton. 'The elements of numbers of plants and times of 
 observation may be expressed by the product of those two factors 
 forming a term which we may call " plant-days." The total number 
 of weevils found upon any class of cotton divided by the number of 
 "plant-days" will give the average number of weevils attracted by 
 each plant for each day, and these numbers furnish a means of direct 
 comparison and show at a glance the average relative attractiveness 
 of each class of cotton. The following table presents these results in 
 comparable form: 
 
 Table X. — Relative attractiveness of various cottons. 
 
 
 Number 
 
 of 
 plants. 
 
 Total. 
 
 Average. 
 
 
 Class of cotton. 
 
 Plant 
 days. 
 
 Weevils Infested 
 found, squares. 
 
 Weevils 
 per plant 
 per day. 
 
 Infested 
 squares 
 
 per 
 weevil. 
 
 Relative 
 attract- 
 iveness. 
 
 
 62 
 
 4,920 
 
 287 
 
 3,507 
 
 0.058 + 
 
 12.2+ 
 
 1.0 
 
 
 
 
 5 
 
 8 
 8 
 
 120 
 552 
 
 808 
 
 11 
 64 
 
 207 
 
 136 
 1,089 
 2,013 
 
 .092 
 
 .116- 
 
 .256+ 
 
 12. \ 
 17.0+ 
 9.7+ 
 
 1.6 [• 
 
 
 2.0 
 
 Egyptian 
 
 4.4 + 
 
 Total of 3 non- Amer- 
 ican cottons 
 
 21 
 
 1,480 
 
 282 
 
 3,238 
 
 .191- 
 
 11.5- 
 
 3. 3- 
 
 An examination of these figures shows that American Upland cotton 
 is less subject to the attacks of the weevil than any of the others, and 
 that Egyptian (Mit Afifi) is by far the most susceptible. The differ- 
 ence in degree is most plainly shown in the column of "relative 
 attractiveness." It would certainly seem difficult to formulate a 
 stronger argument for the cultivation of American cottons alone within 
 the weevil-infested district than is presented by these figures. The 
 weevils gathered so thickly upon the Egyptian cotton that the plants 
 could not produce sufficient squares to keep ahead of the injury, and 
 therefore the average number of infested squares for each weevil is 
 only three-fourths as great with that variety as with less infested 
 kinds, but the average injury to each square was greater than with 
 any other. 
 
 The practical appli3ation of these observations may be emphasized 
 
46 
 
 still further by the statement that in spite of the frequent and care- 
 ful removal of weevils from these cottons during the entire season 
 none of the non- American varieties made a single boll of good cotton, 
 so great was the actual weevil injury to them, while American cotton 
 with the same treatment developed a large number of bolls. 
 
 The results are still further sustained by observations upon larger 
 areas of American and Egyptian cotton under field conditions in three 
 localities in Texas, no weevils being removed from either kind. At 
 Victoria, Tex., on August 26, 1903, an examination showed that 96 
 per cent of Egyptian squares were infested, while an average of 13 
 fields of American showed 75.5 per cent. At Calvert, Tex., on Sep- 
 tember 4, Egyptian showed 100 per cent infested, while the American 
 varieties growing alongside showed 91 per cent. Similar results were 
 found at San Antonio. Though growing in close proximity, the Egyp- 
 tian produced no staple whatever, while the American gave better 
 than an average yield in spite of the depredations of the weevil. 
 
 In accordance with these observations, it appears that in developing 
 a variety of cotton which shall be less susceptible to weevil attack by 
 far the most promising field for work lies among the American varie- 
 ties, and of these the very early maturing kinds are most promising. 
 
 The question of choice of different varieties for food was tested in 
 the laboratory by Dr. A. W. Morrill, by placing squares of two kinds of 
 cotton, American and Egyptian, in alternate rows in a breeding cage 
 (PL XII, fig. 48), so lettered and numbered that each square could 
 be exactly located. Weevils were then placed so £hat they could 
 take their choice of these squares, and observations from 8 a. m. to 6 
 p. m. were made upon the location and activity of the weevils. 
 Though this experiment was repeated four times, no positive evidence 
 was obtained to show that weevils had any choice as to which kind of 
 squares they fed upon. Table XI presents a summary of these results. 
 
 Table XI. — Breeding-cage observations upon weevil choice of American and 
 
 Egyptian squares. 
 
 
 Period of 
 observa- 
 tion. 
 
 Num- 
 ber of 
 obser- 
 va- 
 tions. 
 
 
 American squares. 
 
 Egyptian squares. 
 
 Ex- 
 peri- 
 ment. 
 
 Weevils 
 used. 
 
 Total 
 num- 
 ber. 
 
 In- 
 fested. 
 
 Feed- 
 ing 
 punc- 
 tures. 
 
 Egg 
 punc- 
 tures. 
 
 Total 
 num- 
 ber. 
 
 In- 
 fested. 
 
 Feed- 
 ing 
 punc- 
 tures. 
 
 Egg 
 punc- 
 tures. 
 
 1 
 
 2 
 
 3 
 
 4 
 5 
 
 12 m. to 8 
 a. m 
 
 11.45a.m. 
 to 9.45 
 a. m 
 
 12 m. to 5 
 p.m. day 
 after . . . 
 
 11.45 a. m. 
 to 9 a.m 
 
 6 p. m. to 
 8 a.m... 
 
 Total. 
 
 8 
 
 5 
 
 5 
 5 
 
 1 
 
 10 
 
 10 
 
 10 
 10 
 
 18 
 
 16 
 
 16 
 
 16 
 
 16 
 
 4 
 
 12 
 
 5 
 
 7 
 6 
 2 
 
 15 
 
 19 
 
 25 
 17 
 
 7 
 
 5 
 
 1 
 
 2 
 6 
 
 
 16 
 
 16 
 
 16 
 
 16 
 
 4 
 
 5 
 
 5 
 
 9 
 8 
 2 
 
 12 
 
 13 
 
 27 
 14 
 10 
 
 3 
 
 3 
 
 2 
 3 
 
 
 
 24 
 
 58 
 
 68 
 
 32 
 
 83 
 
 14 
 
 68 
 
 29 
 
 76 
 
 u 
 
Iii experiments I and 2 the American squares were attacked more 
 extensivel} than were the Egyptian, while in experiments 3 and 5 
 greater injury was done to the Egyptian, [n experiment I the smaller 
 number of egg and feeding puncl ares made in i he Egypt ian squares is 
 counterbalanced by I he larger Dumber of squares attacked. Although 
 the totals from these Ave tests show stightly Less injury to the Egyp- 
 tian than to the American squares, it could hardly be expected that 
 two arbitrarily chosen series, even if of the same variety, would show 
 any closer agreement in the points of comparison made in this table 
 
 than is therein shown by the American and Egyptian squares. 
 
 HAS THE WEEVIL ANY oTIIKK FOOD PLANT THAN COTTON? 
 
 The question of the possibility of boll weevils feeding upon some 
 other plant than cotton is one of groat importance. It is a well- 
 known fact that insects which have few food plants usually con line 
 their attacks to closely related plants belonging to the same botanical 
 family, or even genus. Accordingly, most of the plants which have 
 been tested especially are most closely related to cotton. Four species 
 of Hibiscus (If. escult ntus, H. vesicarius, H. manihot, H. moscheutos) 
 were grown and an effort made to see whether weevils would feed 
 upon either the leaves, buds, or seed pods. In no case, however, did 
 they live on any of these for any considerable time, though they fed 
 slightly upon some of the parts. Hibernated weevils starved in an 
 average time of about 4 daj T s with leaves of either okra or Sunset 
 Hibiscus. The buds and seed pods were not formed at that time, so 
 could not be tested. Weevils of the first generation, which had had 
 no cotton for food, were placed upon Sunset Hibiscus, and these 
 starved in an average of 3 or 4 days. First generation weevils, which 
 had fed for a few days on squares, were placed upon leaves, buds, 
 and seed pods of Hibiscus vesicarius. Though the}' fed a little, all 
 starved in an average of about 5 days. A lot of first generation 
 weevils, fed first for several days with squares, were given leaves, 
 buds, and seed pods of okra. More feeding was done by this lot than 
 by any other, all parts being slightly attacked. These weevils lived 
 for an average of 7 days. 
 
 Numerous other plants, including sunflower (Hdianthus annuus), 
 bindweed (Convolvulus repens), the slender pigweed and the spiny 
 pigweed (Amardnthus hybridus and A. spinosus), and western rag- 
 weed ( [ u 1 nibrosia psilostachya), and various other species of weeds and 
 glasses which occur more or less frequently around cotton fields 
 were tested, but in no case was feeding noticed except in the case of 
 weevils supplied with pieces of the stem of sorghum, the stems of which 
 were cut into short lengths and some of the pieces split lengthwise. 
 Upon the exposed, juicy pith weevils fed considerably, but they did 
 not puncture through the hard stem to obtain the juice. The sweet 
 
48 
 
 sap found in the pith sustained weevils for some time in the labora- 
 tory, bu1 where obliged to puncture the stem, as they would be in the 
 field, they would never attack sorghum, except possibly freshly cut 
 stubble. Among the many plants tried, therefore, none has beeu 
 tound to show any capacity for sustaining the lives of weevils in the 
 field in the absence of cotton. 
 
 The question of the original food plant of the weevil has received 
 considerable attention from this Division, the investigations made in 
 Cuba being pari icularly thoroughand conclusive. In that island some 
 varieties of cotton grow wild and are perennial. After most careful 
 search Mr. E. A. Schwarz wrote in the spring of 1903: "There is not 
 the slightest doubt, in my opinion, that the original and only food 
 plants of the weevil are the varieties of Gossypium and here in Cuba 
 the variety known as kidney cotton." The investigations of the 
 Division of Entomology have given special attention to the possibility 
 of the boll weevil breeding on other plants than cotton. Throughout 
 the investigations of Prof. C. H. T. Townsend in southern Texas and 
 in Mexico and the careful studies made by Mr. Schwarz in Texas and 
 in Cuba and the observations made by the writers in Texas every 
 plant closely related to cotton has been most carefully watched, and 
 the uniform failure to find the weevil upon any other plant makes it 
 practically certain that cotton is its only food. 
 
 INSECTS OFTEN MISTAKEN FOR THE BOLL WEEVIL. 
 
 Man}' species of insects have been mistaken for the Mexican cotton 
 boll weevil. Among them the two most commonly reported in Texas 
 have been an acorn weevil (PL XIV, fig. 55) and a species commonly 
 found upon bloodweed or ragweed. The chief reason for the promi- 
 nence of these two species is not that the}' resemble the boll weevil 
 more closely than do others, but rather that their habits bring them 
 into closer proximity with cotton fields and their abundance has led to 
 their more frequent discovery. The acorn weevil has in a number of 
 cases been taken in lantern traps set in cotton fields, and the mistake 
 in the proper identification of the species has given currency to the 
 report that the boll weevils are attracted to lights, which, however, is 
 never the case. There is no authentic record of a single boll weevil 
 having been caught at any light. Only very rarely and under excep- 
 tional conditions will the acorn weevil feed at all upon cotton bolls. 
 
 Though the bloodweed weevil (PL XIV, fig. 5-4) has been taken 
 from cotton plants, no evidence has been submitted showing that it 
 was actually feeding thereon, and it is more likely that such specimens 
 had merely strayed to the cotton from bloodweed growing near. 
 
 Another species of weevil, Desmoids scapalis (PL XIV, fig. 58), is 
 much less common and therefore less frequently mistaken, but resem- 
 bles the boll weevil in general appearance far more closely than does 
 

 
 Fig. 29.— Squares Much Fed Upon. Natural Size. 'Original. 
 
 Fig. 30. 
 
 -Distorted Bloom, Caused by Feeding Upon Large Square. Natural 
 Size. "Original, i 
 
• 
 
 VII. 
 
 Feeding Injuries on Blooms and Bolls. 
 
 Fig. 31, Blooms distorted by feeding punctures, open but imperfect, two-thirds natural >ize: fig. 
 32, small boll riddled by feeding punctures, natural size; rig-. 33, one lock of boll destroyed by 
 feeling punctures, two-thirds natural -ize. (Original.) 
 
!«• 
 
 either of the Bpeoies previously mentioned. This ins<-<-i haa been 
 found attacking white prickly poppy (Argemoru alba) and tumble- 
 weed ( .1 iinifti nflius tjiui cizans) in the spring, and probably breeds on 
 Prionopsis ctliata Nfutl and tin- broad-leaved gum plant (Orindelia 
 sqtuirrosa). 
 
 In general the food habits <>f any species are among its distinctive, 
 specific characters, and as the structural differences arc easily over- 
 Looked and difficult of appreciation by anyone unacquainted with ih<- 
 careful study of insects, a rather full, though by no means complete, 
 lis! is here given of the species which have been reported i<> the 
 Division of Entomology as having been confused with the 1><>11 weevil." 
 Many of the most common species will be found figured among the 
 illustrations. The scientific names of the insects are given because 
 they are definite and refer positively to a single species, whereas the 
 common names are used so loosely that the same name may be applied 
 to a number of species having possibly similar habits. The boll wee^ ii 
 is included in this list, and figures of the adult are given in the plates 
 to facilitate comparison. In many cases no common name lias yet 
 been given to the species. Seven of the species mentioned attack 
 living cotton and five species are found feeding only in decaying bolls. 
 The occurrence of the remainder upon cotton is merely incidental. 
 
 Insects often mistaken for the boll weevil. 
 
 Scientific name. 
 
 Common name. 
 
 Plum gouger 
 Acorn weevil 
 
 Anthonomus grandis Boh Mexican cotton boll weevil 
 
 Anthonomus albopilo&usDietz. 
 
 Authonomus prunicida 
 
 Bala n in US u n if arm is auct 
 
 ( « ntrinuspeniceUus Hbst 
 
 ( < a triii us picumnus Hbst 
 
 Chalcoderm us omens Boh Cowpea-pod weevil 
 
 Desmoris sea pa I is Lee ! 
 
 Desmoria const rictus Say 
 Dorytomus mucidus'Lec. 
 
 I.ixus Icesicollis Lee 
 
 Coccotorus scutellaris ... 
 
 Ba ris stria ta Say 
 
 Boris transversa Say Transverse Baris.. 
 
 Anthribus cornutus Say Horned stem borer 
 
 Usual food plant. 
 
 Cotton squares and bolls. 
 
 Blood- weed weevil 
 
 Apple curculio 
 
 Striped Baris 
 
 Araecerus faaciculatus DeG 
 
 Coffee-bean weevil 
 
 Imbricated snout beetle 
 
 Mexican rose beetle. 
 
 Epicarus inibricatus Say... 
 
 Hylobius juries Hbst 
 
 Khynchites mexicanus Gyll 
 
 Tych ius sordidus Lee 
 
 ( tph ryastes b ituberosus Shp . . . I 
 
 Trichobaris mucorea Lee , Tobacco-stalk weevil. 
 
 «In the preparation of this list we are under obligations for assistance to Mr. 
 F. H. Chittenden, who has also furnished information in regard to the food habits 
 of the species. 
 
 21739— No. 45—04 4 
 
 Plums... .. XIV,57. 
 
 XIY,55. 
 XY, 61. 
 
 Acorns 
 
 Beetle in flowers 
 
 do 
 
 Cowpeapods XV. 63,6 
 
 Broad-leaved gum plant . XIV, 
 
 Plato 
 figure. 
 
 XIV, 52,53. 
 
 Willow. 
 
 Ragweed (Ambrosia spp). XIV, 54. 
 
 Apple XIV. 56. 
 
 Stems of ragweed 
 
 Roots of cocklebur X V. 59, < 
 
 Cotton stems 
 
 Coffee beans and old cot- XV. 62. 
 
 ton bolls. 
 Omnivorous XVI, 69. 
 
 Beetles attack rose 
 
 Common in cotton fields. 
 
 Found on cotton 
 
 Tobacco stalks 
 
50 
 
 Insects often mistaken for the l><>/l weevil — Continued. 
 
 Scientific name. 
 
 Common name. 
 
 Usual food plant. 
 
 Plate 
 figure. 
 
 OTHER BE] PLIS8 
 
 
 
 
 Monocrepidius vespertinus Fab 
 
 
 Larva in grass roots 
 
 XVI. Til. 
 
 Notoxus monodon Fab... 
 
 Cotton-stalk borer 
 
 Larva in ground 
 
 
 Ataxia crypto Say 
 
 Cotton stalks 
 
 XVI, 68. 
 
 0libru8 apicalis Mela 
 
 
 Decaying bolls 
 
 
 Carpophilus hemipterus Linn _. 
 
 
 Develops in decaying bolls 
 
 
 Carpopkilus dimidiatus Fab... 
 
 
 do 
 
 
 Epuixea cestiva Linn 
 
 
 --do.. 
 
 
 ( 'atliartiis gemellatus Dnv 
 
 Grain beetle 
 
 do 
 
 
 Tribolium ferrugineum Fab 
 
 Flour beetle 
 
 Attacks seed 
 
 
 BUGS AND OTHER INSECTS. 
 
 
 
 
 Homalodisca triguetra Fab 
 
 Sharpshooter 
 
 
 XVI, 66, 66. 
 
 Oticometopia undata Fab 
 
 "Waved sharpshooter 
 
 do 
 
 Dysdercus suturellus H-Sch 
 
 Cotton stainer 
 
 Cotton bolls 
 
 XVI Si 
 
 
 
 
 IS COTTON-SEED MEAL ATTRACTIVE? 
 
 LABORATORY OBSERVATIONS. 
 
 On account of the popular impression that cotton-seed meal will 
 attract weevils it has been necessary to conduct a rather full series of 
 experiments. To ascertain the possibility of using this substance as 
 an attractaut for the weevil in field work three series of laboratory 
 tests were first made. The weevils used were obtained from the same 
 source in all tests. The first series was designed to test the ability of 
 the weevils to live upon cotton-seed meal alone as a food. The sec- 
 ond series was intended to show whether the weevils would prefer the 
 meal to cotton leaves as an indication of the possibility of attracting 
 hibernated weevils before the formation of squares in the spring. 
 The third series was planned to show whether the weevils would pre- 
 fer the meal as a food when squares could be easily found. The 
 cotton -seed meal used was obtained fresh from the oil mill and the 
 experiments started during the latter part of November. 
 
 Weevils fed rather sparingly upon the meal in Series I. It did not 
 seem to agree with them as a food and they showed no special inclina- 
 tion to feed upon it. Twenty-three of the 24 weevils confined upon 
 meal alone died in from 2 to 13 days, showing an average length of 
 life of slightly over 6 days. These weevils either starved to death 
 rather than eat the cotton-seed meal or else they were not able to eat 
 ;i . The drj r and empty bodies of all dead weevils showed that death 
 was caused by starvation and not by disease. Being entirely covered 
 with the fine meal did not seem to have any bad effect upon them. 
 As weevils without food or water showed an average length of life 
 slightly over days, agreeing exactly with the period in this test, it 
 appears that cotton-seed meal is not only not a food for the weevil, 
 but also that it is not capable of x>rolonging their lwes to any appre- 
 ciable extent. 
 
51 
 
 In Scries 11 l'I weevils were confined with fresh ootton Leaves and 
 cotton-seed meal as food. During the 297 "weevil-days" that this 
 ezperimenl was eon tinned but one weevil died. The average period 
 of the test for each weevil was ii days. The weevils fed almost 
 wholly upon Leaves. Occasionally one would feed a Little on the 
 meal, hut they certainly preferred the Leaves, and the result* show 
 that Leaves alone were responsible for the Longer Life of these \\<<-\ Us. 
 The 20 survivors were placed in hibernation December _<». L902, but 
 all died before April L5, L903. 
 
 In Series III freshly picked squares were placed with the meal to 
 see winch would attract the weevils. Fresh meal, as well ;^ squares, 
 was supplied at frequent intervals. During the L58 " weevil-days " 
 that thistest continued not one of the 10 weevils died. The average 
 period of the test was almost 10 days, and after it the weevils were 
 placed in hibernation, but all died before April L5, 1903. In only one 
 instance was a weevil observed feeding upon the meal. From this 
 test it was evident that eotton-seed meal has not the power to attract 
 weevils from squares, even when the latter have been picked for 
 several days. 
 
 In spite of the complete failure indicated by these results, a series 
 of field tests was made during the late fall of 1902. 
 
 FIELD TESTS. 
 
 In order to settle this question finally, two series of field tests were 
 made, one during the fall, when weevils were abundant but full-fed 
 and cotton still standing, and the other during the envly spring, with 
 the view of attracting weevils as they came from hibernation before 
 cotton began to square. 
 
 Fall of 1902. — Cotton-seed meal fresh from the mill was placed in 
 10 cheese-cloth bags, which were shaken so that the fine dust from the 
 meal covered the outside of each bag. The bags were numbered and 
 then tied to cotton plants in infested fields at about the middle of the 
 plants. The bags were so distributed as to test fields in which the 
 following conditions prevailed: One field entirely black from frost, 
 one nearly black, one about half green, and one still entirely green. 
 The number of weevils on the plant to which the bag was attached 
 was noted each day to ascertain in a general way the number of wee- 
 vils which would be very near the meal and able to reach it in the 
 ordinary course of travel over the plant without having to fly to it. 
 Weevils on adjacent plants would naturally come within the sphere 
 of influence if such existed, but they were disregarded. After the 
 failure of the meal to attract weevils in the field became apparent, 
 weevils were caught and placed upon the bags to see if they would 
 stay there. 
 
 Altogether 65 observations were made, covering a period from Novem- 
 ber 24 to December 16. The weather was generally cool, averaging 
 
52 
 
 about 61° F., mean temperature, and cotton had ceased to grow. 
 Counting each weevil found at each observation, only 5 were found 
 upon the 10 bags of meal. Of these 5, 3 were hidden in the folds of 
 the cloth for shelter and were not feeding. One weevil was counted 
 twice and was the only one found that appeared to be feeding upon the 
 meal. During this period a total of 163 weevils was found upon the 
 top parts of the plants to which the bags were attached. This is con- 
 siderably below the real number present, because in many instances 
 this examination was not made, and doubtless weevils were overlooked 
 even when examination Avas made. 
 
 At various times 27 weevils were placed directly upon the bags of 
 meal and given every opportunity to show whether they would stay 
 thereon if they accidentally found the meal. Only one of this num- 
 ber stayed upon the bag for 24 hours, and this one remained in the 
 shelter of the cloth. 
 
 The unattractiveness of cotton-seed meal for the weevils seems 
 absolutely proven so far as fall conditions are concerned. 
 
 Sjiring of 1903. — These tests were intended to show whether hiber- 
 nated weevils would be attracted to the meal before squares were to 
 be found in the field. Two series of experiments were planned, using 
 four bags of meal in each. For the location of the first series a field 
 was chosen which was known to have been badly infested with wee- 
 vils up to December 18, 1902. This field was not replanted with cot- 
 ton in 1903, nor was there another field in the vicinity, so that weevils 
 coming from hibernation would find no possible food except the meal. 
 A number of live hibernated weevils was taken from this field, so that 
 there can be no doubt of the presence of many of them. The bags of 
 meal were placed near apparently favorable hibernating places. 
 
 Fift} T -five observations were made under these conditions, but not 
 a weevil came to the bags of meal. 
 
 For the second series a field was selected in which occasional seppa 
 cotton plants were found. The plants had been allowed to stand 
 through the winter in this field, and hibernated weevils were quite 
 abundant. The bags of meal were here attached to stakes driven 
 beside seppa plants. More than 50 observations were made after 
 weevils were known to be out of their winter quarters. Nine weevils 
 were found upon the seppa cotton plants beside which the bags of 
 meal were placed, but not a weevil was found on the meal. 
 
 Only one conclusion can be drawn from these experiments. Under 
 no conditions will cotton-seed meal serve as a food for the weevils, 
 and it shows no power whatever of attracting them. 
 
 THE POSSIBILITY OF BAITING WEEVILS WITH SWEETS. 
 
 ATTRACTIVENESS OF VARIOUS SWEETS. 
 
 On account of the considerable publicity given the theory that it 
 might be possible to destroy the weevil \>y attracting it to sweetened 
 poisons, a number of experiments were performed along this line. 
 
68 
 
 In the course of this work Mr. <i. II. Harris employed in Ihe labors 
 tory tests s Large variety of sweets. White granulated sugar, two or 
 t li pee grades of brown Bugar, two or three grades of molasses, and the 
 best strained hone} were among the Bweets tried. The conditions 
 were such as to lead the weevils to eal the sweets if thej would ever 
 do so. The only alternative offered them for food wasa supply of 
 rather <>1<| cotton Leai es such as weevils never t<>u<-ii in the field. In 
 spite of the unfavorable conditions for getting al the real choice of 
 the weevils theyshowed Little inclination bo feed upon the Bweets 
 except in the case of honey, which seemed to attract them quite 
 Btrongly. .Manx weevilsfed upon the unattractive Leaf tissue or upon 
 the broken end of the petiole rather than upon the sweets. 
 
 The result of Mr. Harris's experiments with undiluted molasses 
 applied to plants in the field as summed up in his own words was that 
 "nothing indicated that the weevils were attracted by the odor of 
 sweets." Honey was then tried, and this did attract a few weevils. 
 Mr. Harris's general conclusion, based upon the results of his experi- 
 ments, was that "while a high grade of sweets seemed to have more 
 attraction than a cheaper grade, neither can be depended upon to 
 attract the weevils for poisoning." 
 
 ATTRACTIVENESS OF SWEETS TO HIBERNATED WEEVILS IN LABORATORY. 
 
 The sweets used in these tests were of three kinds: High-grade 
 molasses, common molasses, and light-brown sugar. The weevils 
 were brought in from the field and left for one week without food or 
 drink previous to the beginning of the tests on April 2, 1903. Three 
 weevils were used with each kind of sweet, the latter being in their 
 strongest form and the sugar in a saturated solution. The inclosing 
 apparatus was formed by placing two bottles mouth to mouth with 
 sufficient space for air, but not enough for the escape of the weevils 
 between them. In the bottom of one bottle was placed the sweet and 
 the second leaves of cotton in the bottom of the other. The weevils 
 were then inclosed, and the cages thus formed were placed in a hori- 
 zontal position in the dark to eliminate every possible influence of 
 direction of light, relative elevation of food, etc. The food suj)plies 
 were renewed occasionally, and the location of the weevils relative to 
 the food in each cage was noted frequently. The weevils were counted 
 at eacli observation. The results of these observations are briefly 
 summarized in the following table: 
 
 Table XII. — Attraction of various streets us. cotton, second leaves. 
 
 Character of sweet. 
 
 Number 
 of ob- 
 serva- 
 tions. 
 
 Number 
 of wee- 
 vils on 
 cotton. 
 
 Number 
 of wee- 
 vils at 
 sweets. 
 
 Best molasses, cage 1 
 
 20 
 13 
 
 18 
 
 86 
 
 29 
 42 
 
 48 
 
 1 
 
 Best molasses, cage 2. . 
 
 5 
 
 Common molasses, cage 3 
 
 4 
 
 Brown-sugar sirup, cage 4 
 
 Total 
 
 21 
 
 8 
 
 72 
 
 144 1« 
 144 
 
 
 
 
54 
 
 These figures become even more striking in consideration of the 
 fact that the cotton leaves were often purposely left until they became 
 moldy and decayed or dried and wholly unfit for food. It was at 
 such times that most of the weevils sought the sweet in preference. 
 Should we leave out of the account the weevils found at the molasses 
 or sirup when the cotton was unfit for food, the number attracted 
 there would be reduced fully one-half. In either case the fact remains 
 that none of the sweets can be said to have attracted weevils from 
 the cotton leaves. 
 
 INFLUENCE OF SWEETENED WATER UPON FEEDING OF WEEVILS ON 
 
 COTTON PLANTS. 
 
 It is easy to demonstrate that weevils will in confinement feed 
 upon sweet solutions. To prove that they will show the same attrac- 
 tion to it in the field is a far more difficult matter. 
 
 For the purpose of these experiments, cheap molasses was used, 
 mixing 1 part of molasses with 25 parts of water, as is generally 
 recommended in spraying formula3. Three pairs of young plants 
 which had not begun to square were then selected from those growing 
 upon the laboratory grounds. The plants in each pair were of equal 
 size, and both in healthy condition and standing closely enough 
 together to be both covered by one cage. One plant of each pair was 
 then dipped in the sweetened water, while the other was left in its 
 natural condition. In each of the cages 10 weevils were then placed 
 upon the ground and midway between the bases of the plants. The 
 object of the test was to see which plant, the treated or untreated, 
 would attract the larger number of weevils. During the first three 
 days observations were made several times each day. Weevils found 
 upon either plant were counted at each observation. 
 
 A summary of the observations made on the first day before the 
 liquid had dried showed 15 weevils upon the sweetened plants and 16 
 on those not sweetened. These results were so remarkably even that 
 no attraction or repulsion could be ascribed to the liquid before it 
 dried. 
 
 During the ten days covered by the observations, however, 63 wee- 
 vils were found upon the unsweetened plants and only 45 upon those 
 sweetened. The weevils fed largely upon the petioles and somewhat 
 upon the blades of the leaves and the main stems of the plants. No 
 indication was observed of special feeding upon the "gloss" left by 
 the drying of the sweetened water. In each cage the normal untreated 
 plant was destroyed before the treated one. During the first half of 
 the observations 52 weevils were found feeding upon the unsweetened 
 plants and only 32 upon the sweetened. Only after every leaf on the 
 untreated plants hung black and dead, while the sweetened plants 
 were in much better condition, did more weevils attack the sweetened 
 plants. 
 
Not <»iil\ »l i<l these tests shoM that molasses in olution has no attrac 
 iion for ili«' weevils, but also that the stick} coating left after the 
 liquid lias dried acts more as a positive repellant to them. 
 
 FIELD TESTS FOR HIBERNATED WEEVILS, USING PI 1:1 HOLA I 
 
 As a final experiment t<> settle the possible usefulness of mola 
 in the weevil fight, a large series of tests was undertaken in ih<- i i < - 1 « ! 
 to see If the pure, undiluted molasses would noi prove attractive to 
 \ur\ Lie as they came from hibernation. To insure a continuous sup- 
 ply of fresh molasses a test tube was nearly filled and then rather 
 tightly plugged with a small stopper wound with cotton. The tube 
 was then fastened in an inverted position to the top of a stake about 
 •J feet Long, and as the molasses gradually oozed through the cotton 
 it ran slowly down Ihe stake, forming a streak of continuously fresh 
 molasses a foot or more in Length. The supply would thus last for 
 several days and was then easily replenished. This apparatus, as 
 shown in PI. XII, fig. 45, was then placed beside a vigorous seppa cot- 
 ton plant in the field at the season when the weevils were beginning 
 to leave their winter quarters and seek food to break their Long fast. 
 Both high and Low grades of molasses were employed in these tests, 
 three t ubes of each being used. Altogether 84 observat Lonswere made 
 between April 24 and .May 15, 11)03, during which period most of ihe 
 weevils emerged from hibernation. 
 
 The results again proved disappointing, for only a single weevil 
 was ever found at the molasses. This individual sipped occasionally 
 at the sweet, wandering up and down the tube in the intervals. It 
 did not appear to be satisfied and did not remain long at or near the 
 molasses, but flew away and was not found there again. 
 
 The failure of the molasses to attract was not due to the scarcity of 
 weevils in the field. During the period of observation 23 weevils 
 were found working upon seppa cotton very near the molasses tubes, 
 and certainly within reach of its attractive influence, provided it had 
 any. More weevils were also found in the same field, but at some- 
 what greater distances from the tubes. 
 
 During the warm days toward the close of the experiment many 
 butterflies, mostly Vanessa atalanta and some Anosia plexippus, came 
 to the tubes. A few specimens representing several species of beet les 
 and many ants Avere also found. 
 
 None of the experiments made, either in the laboratory or in the 
 field at Victoria, Tex., has shown that weevils are attracted in even 
 the slightest degree to any grade of molasses, either in its undiluted 
 or diluted form. No sugar solution has been found to possess any 
 more attraction than does molasses. Honey appears to be an espe- 
 cially attractive sweet, but is too expensive for use in this manner. 
 
 Considering the facts that these experiments have been much more 
 numerous and that they have covered a much broader range of con- 
 
56 
 
 ditions tlian any previously performed, we must conclude that it yet 
 remains to be shown that sweets of any kind have any value in the 
 problem of controlling the boll weevil. 
 
 FEIGNING DEATH. 
 
 This interesting habit of the weevil is its first resort as a means of 
 escape from its larger enemies. It has been the basis of many ma- 
 chines designed to jar them from the plants and to collect them in 
 convenient receptacles. If jarred from the plant, the weevil falls to 
 the ground, with its legs drawn up closely against the body and the 
 antennre retracted against the snout, which is brought inward toward 
 the legs. The position is characteristic and can be more easily shown 
 than described. See PI. I, fig. 2. In this position it often remains 
 motionless for some time. If further disturbed, so that it finds that 
 its ruse has failed to conceal it, it will start up quickly, run a little 
 way, and again fall over, feigning death. The color of the weevil 
 so closely resembles that of the ground that it is quite difficult to find 
 a fallen individual so long as it remains quiet. The habit is of great 
 value in protection. If left undisturbed until it believes danger to 
 be past, it recovers its footing and returns to the plant. 
 
 REPRODUCTION. 
 
 Under this general heading we present some of the most interesting 
 observations which have been made upon the habits of the boll wee- 
 vil. The relation of the sexes, the evident selection of clean squares 
 for egg deposition, the great destructive power of the weevil, the 
 rapiditj- of development, and the influence of varying temperatures 
 upon its activity and development may also be classed as among the 
 most important as well as most interesting observations. 
 
 METHOD OF MAKING FIELD OBSERVATIONS UPON WORK OF 
 
 WEEVIL. 
 
 For the purpose of field study large cages (3 by 3 by 4 feet) were 
 made, the covering being of fine wire screening (PI. IX, fig. 36). 
 Uninfested plants having plenty of squares were found by a careful 
 examination of each square and inclosed by the cages. The number 
 of weevils placed in each cage was varied according to the number of 
 squares within, ranging from 2 to 5 at various times. In making the 
 daily observations the cage was entered and each square examined. 
 Each square found attacked in an} 7 way was marked with a numbered 
 tag containing full data as to the lot of weevils and the number pres- 
 ent, date, and nature of injury (PI. IX, fig. 37). After all weevils 
 had been found the cages were removed to new uninfested plants for 
 another day's work. Close watch was kept upon all tagged squares 
 upon succeeding days, and every important change taking place in 
 each square was added to the record on the tag. The special points 
 

 Platt VIII. 
 
 External and Internal Injury from Feeding on Bolls. 
 
 Fig. 34, External appearance of large boll much fed upon, natural size: tig. 35, internal appear- 
 ance of same boll, natural >i/e. , < Original, i 
 
• 
 
 I 
 
 Fiq. 36.— Cages Used to Confine Weevils in Field. (Original). 
 
 Fig. 37.— Plant Showing Tagged Squares from Cage Work. 'Original, i 
 
i 
 

 p 
 
 Egg and Feeding Punctures: Effects on Squares and Bolls. 
 
 Fig. 38, lioll showing two locks destroyed by two feeding punctures made by a male weevil, two- 
 thirds natural size: tii. r . 39, square showing external appearance of two egg punctures, natural 
 size: fig. 40. wart formed on side of square in healing an egg puncture, natural size: fig. 11. egg 
 deposited on inside of carpel of a boll, two-thirds natural size: fig. 12, normal ami flared 
 squares, natural size. (Original.) 
 
noted in each case, bo far as was possible, were: The formation of a 
 distinct wart; time of flaring, yellowing, and falling; the emergence 
 of adult; presence of a parasite; death of larva, pupa, etc. A very 
 complete historj of each square was thus obtained. During the sea 
 son of 1903 three Bpecial periods wen- selected for stud} of this kind. 
 The first was taken during the early pari of June, when hibernated 
 weevils only were active, the second was taken in August for the 
 work in midsummer, and the third in the latter part of October for 
 the Btudy of the development of lat<- weevils. Altogether in these 
 three series over a thousand squares were tagged and recorded. The 
 work of males was compared with that of females in this way, as 
 were also the developmental periods in squares and bolls. Although 
 requiring a great deal of time and close attention, the numerous defi- 
 nite observations obtained abundantly justified the work required. 
 
 FERTILIZATION. 
 AGE OF BEGINNING COPULATION. 
 
 After the adult weevils have left the squares a certain period of 
 feeding is necessary before they arrive at full sexual maturity. This 
 period varies in Length according to the effective temperature prevail- 
 ing and appears to bear about the same ratio to the developmental 
 
 period as does the pupal stage. 
 
 Among the many weevils kept from emergence till death for the 
 purpose of ascertaining the length of life without food, copulation 
 was never observed. With weevils fed upon leaves alone the period 
 preceding copulation is about twice the normal length in the cases 
 observed of those having squares to feed upon. 
 
 During the hot weather this period appears to be on the average 
 only about three or four days in length, while as the weal her becomes 
 colder it increases gradually until weevils may become adult, feed 
 for a time, and go into hibernation without having mated. ' A single 
 union seems to insure the fertility of as many eggs as the average 
 female will lay, and its potency certainly lasts for a period fully equal 
 to the average Length of life. 
 
 SEXl'Ai. ATTRACTION AND DURATION OF COPULATION. 
 
 The distance through which the attraction of the female will influ- 
 ence the male varies extremely. To ascertain how far the attraction 
 might be exerted in the case of the "boll weevil, 2 females were con- 
 fined with food in a small bottle covered with cheese cloth, and the 
 bottle was then placed in a horizontal position inside a Held cage and 
 near its top. Within this cage were 3 males which had been confined 
 there alone for 4 weeks. The bottle containing the females was so 
 placed as to be within a tew inches of the top of a cotton plant upon 
 
58 
 
 which the males were working and touching the leaves of the plant, 
 in order to afford the males access to the bottle without having to fly 
 to it. 
 
 Close watch was kept, but during 11 days not a male was seen to 
 go near the bottle. At the end of that time the females were taken 
 into the laboratory, as was also one of the males from the cage. All 
 were removed from squares and, being placed upon the table, were 
 brought gradually nearer together. The male paid no attention 
 whatever to the nearest female until brought within an inch of her. 
 He then went directly to her. The sense of smell appeared to guide 
 his movements. The fact that this male mated readily with both of 
 the females used in the cage shows that the only reason for failure t o 
 attract in the cage lay in too great distance separating the sexes. 
 
 These observations are entirely borne out by those made in the 
 field. The fact appears to be that the sexes are attracted only when 
 they meet either on the stems or upon the squares of a plant. The 
 comparative inactivity of the male has a bearing on this matter. 
 The general conclusion is that instead of seeking widely for the 
 females, the males are content to wait for them to come their way. 
 The greater comparative activity of females is shown in the stud3 T of 
 their food habits. 
 
 In a number of cases that were timed the average duration of the 
 sexual act was very nearly thirty minutes. 
 
 DURATION OF FERTILITY IN ISOLATED FEMALES. 
 
 A number of females which were known to have mated were isolated 
 to determine this point. Although neither limit was exactly deter- 
 mined, the results proved veiy striking. Several of these females 
 laid over 225 eggs each and nearly all of them proved fertile. Select- 
 ing three cases in which the facts are positively known, it appears that 
 fertility lasted for an average of something over GO days and that 
 during this period these females deposited an average of nearly 200 
 eggs. The maximum limits may possibly be considerably higher than 
 
 these. 
 
 OVIPOSITION. 
 
 AGE OF BEGINNING OVIPOSITION. 
 
 Normal oviposition seems never to take place until after fertiliza- 
 tion has been accomplished, but it usually begins soon after that. 
 Observations upon the age at which the first eggs are deposited can 
 be made more easily and more positively than those upon the age at 
 which fertilization takes place. In a general way, therefore, the 
 observations here given may be considered as also throwing light 
 upon the time of beginning copulation. 
 
 In the breeding of weevils from eggs deposited by hibernated females 
 a number of observations accumulated upon this point and another 
 series was made in the fall of 1902. The results of both series are 
 given in Table XIII. 
 
59 
 
 Tabli XIII. !'/• of beginning ovijwmt ion. 
 WEEVILS I »r FIRST OENERATK IN, 1908. 
 
 Date adult 
 
 Date of th-st egg. 
 
 Number 
 
 ..i i. 
 malefl 
 
 i 
 time 
 
 9 ii 
 
 '.Ml 
 
 .-, o 
 
 I ii 
 
 7.0 
 
 5.0 
 
 id 
 
 
 1908. 
 .1 one R to 9 
 
 1908 
 June \!i t.. 18 
 
 :f 
 l 
 
 i 
 
 i 
 
 i 
 
 
 June in 
 
 .linn' I'.i 
 
 '.i ii 
 
 .lllll.' II 
 
 .Inn.- 18 
 
 :■:, ii 
 
 
 do 
 
 1 II 
 
 Do 
 
 .luii.- I'.' 
 
 III) 
 
 June 13 
 
 June i'- 
 
 50 
 
 June 13 t<> 1 1 
 
 .i.. 
 
 85 'I 
 
 
 .1., 
 
 16 H 
 
 
 
 
 Total 
 
 27 
 
 
 
 150 ii 
 
 
 
 
 
 
 
 
 WKKVILS BRED IN FALL <»F imr.'. 
 
 1908. 
 
 September 4 to 5 . . 
 
 1902. 
 
 September 17 
 
 September 16 
 
 October 16. 
 
 November \r> to 17... 
 November l'.i 
 
 8 
 
 •") 
 
 4 
 
 3 
 
 12.5 
 
 7.(1 
 14.0 
 7.0 
 
 8 ii 
 
 87.5 
 
 September 9 
 
 35.0 
 
 October 2 
 
 56.0 
 
 November 9 1 >ll 
 
 49.0 
 
 November 11 
 
 24.0 
 
 
 
 Total 
 
 22 
 
 
 801.5 
 
 
 
 «».<)+ 
 
 
 
 
 
 
 The average time of 5.5 days, as shown by the firsi generation, is 
 probably about a day and a half longer than the minimum average 
 
 period during the hottest weather, while the 9-day average found from 
 September 4 to November 11 is considerably short of the maximum 
 average just before hibernation. 
 
 EXAMINATION OF SQUARES BEFORE OVIPOSITION. 
 
 In the course of a great many observations upon oviposition it 
 was found that females almost invariably examine a square quite 
 carefully before they will begin a puncture for egg deposition. This 
 examination is conducted entirely by means of senses located in the 
 antennse and not at all by sight. In fact, the sense of sight appears 
 to be of comparatively small use to the weevil. 
 
 In regard to the actual time spent in the work of examination before 
 beginning a puncture 60 observations were recorded. These 1 show 
 that the average time is over two minutes. 
 
 This examination of squares is made by females only when they 
 intend to oviposit. Males have never been observed acting in this 
 way, nor do females generally do so when their only object is to feed. 
 
 SELECTION OF UNINFESTED SQUARES FOR OVIPOSITION. 
 
 So unerring is the sense by which examination is made that in a 
 few cases it was able to discover an infested condition no external sign 
 of which was visible to the writer's eye. A female which was under 
 elose observation examined the square given her in the usual manner, 
 but though evidently searching for a place to oviposit and anxious to 
 
60 
 
 do so, she plainly objected to placing an egg in that particular square 
 The writer again examined the square carefully, but found no sign of 
 infestation and replaced it in the observation cage. Again the female 
 made her usual careful examination and still she plainly refused to 
 oviposit. Upon removing the covering from the square it was found 
 to contain an egg^ but the puncture made in depositing it had healed 
 so smoothly that it had thrice escaped observation. The same female 
 was then given two squares, one of which was known to be infested, 
 the latter being placed nearer her. She examined it carefully, then 
 left it, and went at once to the clean square, in which, after the usual 
 examination, she deposited an egg. 
 
 The acuteness and accuracy of the preliminary examination is also 
 well shown by the fact that when provided with more squares than 
 they have eggs to deposit they rarely place more than one egg in a 
 square. It was frequently found, however, that when a female depos- 
 ited just as maii3 T eggs as there were squares present she would place 
 two eggs in one and then make only feeding punctures in the remain- 
 ing square. 
 
 The observations were made upon a large number of females; so 
 there can be no doubt that the habit of selection is general. The 
 conditions provided in these experiments were intended to resemble 
 those existing in a slightly infested field early in the season, where each 
 female could easily find an abundance of clean squares in which to 
 deposit her eggs. Therefore only those cases were recorded in which 
 the number of squares present equaled or exceeded the number of 
 eggs deposited. Where a totally infested condition is reached no 
 choice between infested and uninfested squares could be exercised, 
 and then unless the female happened to be in a condition to refrain 
 from oviposition she would be forced to deposit more than one egg 
 in a square. 
 
 Not only do females show a strong inclination to place only one egg 
 in each square, but the}' also object to making both egg and feeding 
 punctures in the same square. That these conclusions are well 
 grounded may best be shown by giving a summary of two long series 
 of observations, the first made in the laboratory in the fall of 1902 
 and the other made in the field partly in the fall of 1902 and partly in 
 the spring of 1903. 
 
 LABORATORY OBSERVATIONS. 
 
 Nine females were used in this series of experiments. The time 
 followed varied with each individual, but ranged from October 23 to 
 December 18, 1902. During this period a total of 868 uninfested 
 squares was supplied to these 9 females. Of these squares 238 were 
 not touched, while 630 were punctured, either for oviposition or for 
 feeding or for both. The general results are here summarized in 
 tabular form. 
 
 
61 
 
 Tabi i XIV. s * lection of mptarea and relation oj feeding to <>ri/„, 
 
 So 
 
 Of !■■ 
 
 male. 
 
 Period of obeer\ ation. 
 
 Square! 
 supplied 
 
 Squares 
 
 with 1 
 
 Squarei 
 
 with 8 
 
 Square! 
 
 fed "ii 
 onlj 
 
 Bquai 
 with Square! 
 
 Ix.th ini 
 ind touched, 
 ng. 
 
 l 
 
 :\ 
 
 i 
 
 8 
 
 . 
 
 8 
 9 
 
 1900. 
 » October 88 t<> November 16 
 October 88 to Novemtx 
 ( fctober 'J"> t<> November '< 
 ( October 23 to I tetober 88 
 « tetober ~':; to < tetober 88 
 N..\ ember m to 1 December 5 
 November 10 to N"\ ember 85 
 N'..\ ember in t<> December 18 
 November 1 1 t « > December 12 
 
 Total 
 
 L86 
 171 
 96 
 
 91 
 
 L07 
 
 128 
 
 108 
 
 ".i 
 18 
 :«i 
 ■M 
 41 
 L8 
 68 
 
 i 
 
 I 
 
 
 
 i 
 ii 
 
 8 
 
 1 
 8 
 
 6 
 
 ■ 
 
 I 
 
 18 
 16 
 
 I 
 
 7 
 1 
 I 
 
 1 
 1 
 1 
 6 
 
 81 
 
 g 
 
 g 
 
 8 
 
 -,i 
 
 16 
 
 
 
 477 
 
 19 
 
 lln 
 
 
 
 
 
 
 .V Little calculation from these results shows thai 82.5+ I M ''* ( ' (>|11 (, 1 
 all squares attacked received eggs and thai 91.7+ per cenl of all 
 squares oviposited in received only one egg each. The squares which 
 were fed upon only formed 17.5— per cent of the total number 
 attacked, aud those receiving both egg and feeding punctures consti- 
 tute only 3.8 per cent. The squares receiving two eggs each also form 
 3.8 per cent of all the squares which received eggs only. 
 
 The tendency to confine egg and feeding punctures to separate 
 squares is strongly emphasized by the fact that in 17 instances, in 
 which a total of 116 squares was provided, 91 received eggs only, while 
 the remaining 25 were fed upon only; another total of 78 squares 
 received 88 eggs in 72 of them, while the remaining 6 were fed upon 
 only. As these two lots include nearly one-third of all the squares 
 punctured, the tendency may be clearly seen. 
 
 FIELD OBSERVATIONS. 
 
 For one series of observations 500 infested squares were picked 
 promiscuously in the field between May 28 and June 9, 1903. 
 
 A previous field examination was made about the middle of Septem- 
 ber, 1002, and this furnishes some very interesting comparisons as to 
 the weevil's work upon the squares, especially at the beginning of the 
 infestation and after it had reached its height. To facilitate an easy 
 comparison, the results are arranged in Table XV. 
 
62 
 
 Table XV. — General results of observations upon selection of squares. 
 
 
 £ 
 M 
 
 3 
 
 7a 
 
 c 
 
 Squares with 
 1 egg each. 
 
 Squares with 
 more than 
 1 egg each. 
 
 Squares with 
 
 Wh egg 
 and feeding 
 punctures. 
 
 Squares fed 
 
 on only. 
 
 
 S 
 
 Percentage of 
 all squares 
 receiving 
 eggs. 
 
 
 
 | 
 
 o a 
 
 0> c3 P 
 Ah 
 
 <s> 
 A 
 3 
 pi 
 ft 
 
 ©s 
 
 i 
 
 a 
 
 9 
 
 cc 
 II 
 
 ©•g 
 
 Squares infested in laboratory 
 Oct. 23 to Dec. 2, 1903 
 
 Squares picked in field May 28 to 
 June 9, 1903 
 
 Squares picked in field Sept. 17 to 
 22,1902 
 
 630 
 
 500 
 105 
 
 477 
 
 317 
 
 56 
 
 91.7 
 
 79.2") 
 
 62.9 
 
 19 
 83 
 33 
 
 3.8 
 20.75 
 37.1 
 
 24 
 50 
 46 
 
 3.8 
 10.0 
 43.8 
 
 110 
 110 
 16 
 
 17.5 
 20.0 
 15.2 
 
 
 
 
 
 Total 
 
 1,235 
 
 850 
 
 "84.y 
 
 135 
 
 ...... 
 
 "iO" 
 
 120 i. 
 
 97 
 
 236 
 
 
 Average percentage 
 
 18.3 
 
 
 ' 
 
 
 
 
 A few obvious conclusions may well be stated here. Throughout 
 the season from one-fifth to one-sixth of the squares injured were 
 destroyed by feeding punctures alone. Within this small portion 
 must be included most of the work of males and also of newl3~ 
 emerged females before they reach sexual maturity. As the weevil 
 injury overtakes the production of squares it becomes increasingly 
 difficult for females to find clean squares, and they are forced to 
 deposit eggs in squares already injured and also to feed upon squares 
 which already contain eggs. These conditions serve to increase most 
 rapidly the proportion of squares containing both egg and feeding 
 punctures. This is still further emphasized by the fact that in June 
 onty 30 per cent of all injured squares contained feeding punctures, 
 while in September nearly 60 per cent had been thus injured. When 
 females have access to an abundance of squares, they will deposit 
 more than one egg onl} T in about one-fifth of those in which they ovi- 
 posit, while the proportion of those having both egg and feeding 
 punctures is still smaller. 
 
 The tendencies to keep egg and feeding punctures separate, as well 
 as to deposit only one egg in a square, serve to produce the greatest 
 injury of which the weevils are capable for two obvious reasons : First, 
 because where several eggs are placed in one square it is rarely the 
 case that more than one larva develops. If two or more hatch in a 
 square, one is likely to destroy the others when their feeding brings 
 them together. They bite savagely at anything which irritates them, 
 and larvae have been found in the actual death struggle. Second, 
 should eggs be placed in squares which already contained a partly 
 grown larva, those hatching would likely find the quality of the food 
 so poor that they would soon die without having made much growth. 
 One egg will insure the destruction of the square, and a number of 
 eggs, could all the larvae live, would do no more. Therefore it is 
 plain that the possible number of offspring of a single female is 
 
c:; 
 
 increased directly in proportion to the number of her eggs that she 
 places one in a square, and favorable Pood conditions for the larva 
 are best maintained by avoiding feeding upon squares in which • 
 have been deposited, and also by refraining from ovipositing in squares 
 which have been much fed upon. These habits of selections are, 
 therefore, of the greatest importance in the reproduction of the weevil, 
 since thej insure ih< i most favorable conditions for the maturity of 
 the largest possible number of offspring. In ol her words, I hese habits 
 enable the weevil t<> do the greatest damage of which it is capable 
 while the cotton crop is "making." 
 
 These habits are perhaps less strongly marked in the case of l><>lls, 
 though st ill plainly manifested. Feeding and oviposit ion are common 
 in the same boll, but unless the infestation is very great indeed it 
 appears that only rarely is more than one egg placed in one lock, 
 though several are often deposited in the same boll. The number de- 
 posited depends considerably upon the size of the boll. The smallest, 
 which have just set, receive but one, as do the squares, and these fall 
 and produce the adult weevil at about the same period as in the case 
 of squares. Bolls which are larger when they become infested are 
 often found to be thickly punctured and sometimes contain 6 or 8 
 larvae. The weevil seems to know when the food supply is sufficient 
 to support a number of larva' and deposits eggs accordingly. 
 
 ACTIVITY OF WEEVILS IN DIFFERENT PARTS OF THE DAY. 
 
 The 5 females used in these tests were kept in a field cage on pre- 
 viously uninfested plants, and examinations of their work were made 
 mostly at four-hour intervals from G a. m. to 6 p. m. The exact work 
 found was recorded upon tags attached to the squares themselves. 
 Temperature readings were taken at the same time as the observa- 
 tions. The results are most clearly presented in tabular form (p. 64). 
 
64 
 
 Table XVI. — Activity of jive weevils in differt at parts of the <l<i;/. 
 
 Date. 
 
 Period. 
 
 Tem- 
 pera- 
 ture. 
 
 T. 
 
 Ti 
 
 : - 
 
 r 
 
 be 
 
 '. 
 
 :§ 
 at 
 
 bo 
 
 c 
 
 'S . 
 - •/. 
 
 4 £ 
 
 ~ z Condition of 
 ; g weevil ut end 
 fed of period. 
 
 ,2 B 
 
 -'- 
 
 Remarks. 
 
 1909. 
 
 Sept, 2 
 
 Sept. 2-3.- 
 
 Sept.3 
 
 Do 
 
 Do 
 
 Sept. 3 !___ 
 
 Sept. i..... 
 
 Do 
 
 Do 
 
 
 93-60 
 
 80-69 
 
 69-*5 
 
 85-95 
 95-64 
 
 84-68 
 
 68-63 
 
 83-91 
 91-62 
 
 82-79 
 
 IB 
 
 :; 
 
 12 
 
 18 
 12 
 
 3 
 
 4 
 
 24 
 11 
 5 
 
 15 
 
 1 
 
 10 
 
 15 
 11 
 
 1 
 
 1 
 
 19 
 
 8 
 
 
 
 (i p. in. to 6 a. m 
 
 6.15 to 10.15 a. m 
 
 10.40 a.m. to 2.40p.m. 
 3 to 6.30 p. m ..- 
 
 6.30 p.m. to 6 a.m. 
 
 6.30 to 10a. m 
 
 10 a.m. to 4 p. m 
 
 4 to6p.m 
 
 (5 p.m. to 9a. m 
 
 Total 
 
 2 
 2 
 
 10 
 6 
 
 3 
 
 4 
 12 
 
 plant. 
 All resting 
 
 All active 
 
 do 
 
 Placed on fresh 
 
 plant. 
 All resting 
 
 3 moving to ad- 
 jacent squares. 
 All active 
 
 Punctures black 
 
 at 6 a.m. 
 3 trying to escape; 
 
 cage moved. 
 ( Jage moved. 
 
 Feeding punc- 
 tures all black; 
 small square 
 flared. 
 
 Sept. 4-5.. _ 
 
 6 
 
 All feeding 
 
 Cloud v: every 
 wtevil on same 
 square as at 6 
 p. m. 
 
 
 
 108 
 
 81 
 
 60 
 
 
 An examination of these figures shows that weevil activity began 
 and ceased at about 75° F. Activity increased as the temperature 
 rose, and its maximum coincided with the maximum of dailv tern- 
 
 FAHREN- 
 HEIT 
 
 TIME 
 
 12 p Iam 2 3 4 5 6 7 8 9 10 II 12m Ipm 2 3 4 5 6 7 8 9 10 II I2p 
 
 100° 
 95° 
 90° 
 85° 
 80° 
 75° 
 70° 
 65° 
 60° 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . \\ 
 
 pji 
 
 //// 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 rf| 
 
 
 
 
 ^<^. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4 
 
 K' 
 
 ' 
 
 
 
 
 
 NV. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 / / 
 / 
 
 
 
 
 
 
 
 \ 
 
 
 7. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 $ 
 
 
 
 
 
 
 
 
 
 
 
 ^^ 
 
 
 
 
 
 
 
 
 
 
 
 t,„ 
 
 r?tf' 
 
 >rt 
 
 & 
 
 
 \ 
 
 Or 
 
 *ra 
 
 ye t 
 
 'Let 
 
 VI 
 
 V o 
 
 ''/'- 
 
 '•/' 
 
 /('// 
 
 ojU 
 
 •w 
 
 ■ri- 
 
 lls 
 
 
 
 
 
 
 
 
 
 ty— 
 
 
 
 
 
 
 
 
 
 vj 
 
 epi 
 
 em 
 
 bei 
 
 'J, 
 
 f 6 . 
 
 ;./ 
 
 HK 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Fig. 3. — Diagram showing average activity of five female weevils. (Original.) 
 
 perature. It then decreased with the falling temperature until it 
 ceased entirely some time during the evening, probably at about 
 75° F. See fig. 3. Feeding continued at lower temperatures than 
 oviposition, as is known to be the case during the late fall. 
 
 Examinations made in the field between 6 and 7 a, m. on Septem- 
 ber 4 showed that all weevils, both males and females, were quietly 
 resting at that time with the temperature at about 70° F. On cloudy 
 days the activity is less than it is on clear days. 
 
 

 ■ XI. 
 
 Fig. 43.— Three Large Larv/e in a Boll, Two-thirds Natural Size. 'Original.*. 
 
 Fig. 44.— Four Pupal Cells from Bolls ion Left* Compared with Four Cotton 
 Seeds ion Rights Natural Size. (Original.) 
 

 Plati XII. 
 
 Testing Devices. Fallen and Hanging Infested Squares. 
 
 Fig. 15, Device used to test attraction of molasses in the field in the spring; fig. 46, fallen squares 
 on ground in field; t i lt . 17. infested squares dried and still hanging upon the plant: fig. 48, device 
 used to test relative attractiveness to weevils of American and Egyptian squares. (Original, i 
 
PL \» B OF i .1 H ■ i'i:i'< >S1 i n »v 
 
 The Location of egg punctures, while variable, >till shows some 
 selection on the pari of the weevil. This maj be due partly to the 
 form of i he squares and pari ly also to I he size of I h<- we< vil, bu1 w hal 
 
 e\< r the explanation the facl remains ihai in a majority of cases the 
 egg puncture is made on a line aboul halfway between the base and 
 tip of the square. When so placed the egg comes to resl either jusl 
 inside the base of a petal or among the lowest anthers in the square, 
 according to the varying thickness of the floral coverings at thai 
 point (PI, I, fig, •'!). Punctures are very rarely made below this line, 
 though they are sometimes made nearer the tip. Almost invariably 
 the egg puncture is started through the calyx in preference to the 
 more lender portion of the square, where the corolla only would need 
 to be punctured. The reason for the choice of this location may be 
 found under the subject of the " Relation of warts to oviposit ion," on 
 page »'> ( .». 
 
 With bolls no selection of any particular location has been found, 
 but eggs seem to be placed in almost any portion. PL X, fig. 41, 
 shows the egg deposited inside the carpel. 
 
 POSITION OF THE WEEVIL WHILE PUNCTURINO FOR OVTPOSITION. 
 
 While engaged in making c^j; punctures the favorite position of 
 the weevil is with its body parallel to the long axis of the square and 
 its head toward the base of the same. The tip of the weevil's body 
 is thus brought near the apex of the medium size square. Having 
 selected her location, the female takes a firm hold upon the sides of 
 the square and completes her puncture while in this position. It may 
 be that the position described is especially favorable for obtaining a 
 firm and even hold, and this may have something to do with the reg- 
 ularity with which it is assumed. If so, the apparent choice 4 of this 
 location for the puncture is only partially explained, since it has been 
 often shown that weevils can puncture and oviposit successfully in 
 almost any portion of the square except its very tip. 
 
 Undoubtedly there are other reasons than those of mere conven- 
 ience which have so impressed themselves upon the inherited experi- 
 ence of the weevils as to lead them to the choice of this position and 
 the consequent location of the punctures and eggs. Most apparent 
 of these reasons, and probably also most important, is the advantage 
 which this location affords in the protection of the egg and the young 
 larva developing from it against the attacks of natural enemies as 
 well as from the injurious effects of drying and decay. 
 
 This protection is readily explained by several facts. The place 
 chosen is through the thickest and toughest portion of the floral 
 envelopes through which the anthers can be reached, since the thick- 
 est parts of Doth calyx and corolla are toward their bases. More 
 21739— No. 45—04 5 
 
66 
 
 important than the thickness of the layers of vegetable matter is the 
 character of the tissues through which the puncture passes. Though 
 corolla and calyx are both modifications of original leaf tissue, both 
 have changed so greatly in form and texture that the resemblance is 
 recognized only by those somewhat acquainted with plant structure. 
 The corolla, moreover, has changed far more than has the calyx, and 
 in becoming so highly specialized its tissue has lost certain powers 
 still retained by the green calyx tissue. The particular power referred 
 to in this connection is the ability to heal small wounds. Punctures 
 made in the corolla must, therefore, remain open, while small punc- 
 tures through the calyx will in most cases be healed by the natural 
 outgrowth of the tissue, so as to completely fill the wounds in a man- 
 ner entirely analogous to the healing of wounds in the bark of a tree. 
 The custom of the weevil of sealing up its egg punctures with a mix- 
 ture of a mucous substance and excrement is of great advantage and 
 assistance to the plant in the healing process. While undoubtedly 
 applied primarily as a protection to the egg, it serves to keep the 
 punctured tissues from drying and decay, and thus promotes the 
 process of repair. 
 
 As a result of the growth thus stimulated in the calyx, the wound 
 is perfectly healed in a short time, and, as is the case in the healing 
 of the bark of trees, here also we find a corky outgrowth projecting 
 above the general surface plane. This prominence the writer has 
 termed a ' ' wart" (PI. X, fig. 40). The healing is completed even before 
 the hatching of the egg takes place, and thus both egg and larva par- 
 take of the benefit of its protection. 
 
 It is possible for the puncture to heal without the full development 
 of the wart, and it is also possible for eggs to develop successfully 
 even when the puncture was made through the corolla alone and no 
 wart developed, but in the latter case the chances are rather against 
 it. Occasionally warts do develop from feeding punctures which 
 were small, but the exact conditions under which this takes place 
 have not been determined. 
 
 THE ACT OF OVIPOSITION. 
 
 The general process of making punctures has been described pre- 
 viously under the topic of "Food habits" (p. 38), and will there- 
 fore not be repeated here. Having completed the formation of the 
 egg cavity, the female withdraws her proboscis and turns end for 
 end. She depresses the tip of her abdomen and locates therewith the 
 opening to the cavity by feeling or scraping around. In a majority 
 of cases the opening is readily found, but sometimes it is not. Then 
 the female seems often to lose all sense of locality, but continues 
 scraping with the tip of her abdomen. If she is still unsuccessful, 
 she turns and continues the search by means of the antenna?, just 
 
 
61 
 
 .is in tin- preliminary examination of a square before beginning a 
 puncture. 
 
 In many oases females were not Iced to ad aally place I be I Lp of I be 
 proboscis within the opening of the cavitj without Beeming to be 
 aware of its proximity. Wnen the cavitj has been round again by 
 the antenna! senses, the female invariably enlarges it before turning 
 again to inseri the ovipositor, [f the search with the antenna) does 
 not prove successful, the female will make another puncture in the 
 same manner as al first, appearing to know that no egg has yet been 
 placed in thai square. 
 
 After locating the cavity by the tip <>f the abdomen, the ovipositor 
 is first protruded to the bottom) of tlie cavity, in which it appears to 
 be firmly held in position by the two terminal papilla? and the power 
 of enlarging the terminal portion of the ovipositor. Slight contrac- 
 tions of the abdomen occur while this insertion is being made. In a 
 few moments much stronger contractions maybe seen, and often a 
 firmer hold is taken with the hind legs as the egg is passed from the 
 body, and its movement may be seen as it is forced along within the 
 ovipositor and down into the puncture. Only a few seconds are 
 required to complete the deposition after the egg enters the opening 
 to the cavity. The ovipositor is then withdrawn, and just as the tip 
 of it leaves the cavity a quantity of mucilaginous material, usually 
 mixed with some solid excrement, is forced into the opening and 
 smeared around over the same by means of the tip of the abdomen. 
 This seals the egg puncture and the act of oviposition becomes com- 
 plete (PL X, fig. 39). 
 
 TIME REQUIRED TO DEPOSIT AN EGG. 
 
 Observations upon this point were very conveniently made by con- 
 fining females upon squares from which the involucres had been 
 removed. A plain glass cover allowed accurate observations, which 
 were made to the fraction of a minute. The time required to com- 
 plete the excavation and the time required to place the egg were the 
 two points especially noted. 
 
 The time of making the puncture was noted in 115 instances, and 
 this was found to average 5^ minutes. The time varied widely, being 
 from 1 to 13 minutes; the usual range was from 4 to 8 minutes. 
 From the time that the weevil began to puncture till the sealing of 
 the cavity the complete act of oviposition required in 103 instances 
 an average of slightly over 7^ minutes, ranging in time from 3 to 16 
 minutes. 
 
 As these observations were made between October 7 and 23, the 
 periods given may be slightly longer than they would be in warmer 
 weather. However, various observations made in the field in mid- 
 summer agree very closely with the averages given. 
 
68 
 
 llkTE OF OVIPOSITION. 
 
 Since the period of reproductive activity of the boll weevil is so 
 Long, tin 1 rate at which eggs are deposited is a question requiring much 
 time for its determination. There have been found great variations 
 in the rate at different seasons, and it is clear that oviposition is even 
 more strongly influenced by variations in temperature than is feeding. 
 The rate sometimes varies unaccountably and very abruptly with the 
 same female upon succeeding days. No explanation for this has as 
 yel been found. The rate is influenced also by the abundance of 
 chan squares which the weevil can find, so that it is greater in the 
 early season, as the degree of infestation is approaching its limit, than 
 after infestation has reached its maximum. 
 
 Two extended series of observations have been made to determine 
 especially the normal average and the maximum ability of the female. 
 
 AVERAGE. 
 
 Taking first 54 females which had gone through hibernation, we 
 find that they deposited on the average 2^ eggs each daily in the 
 laboratory, and 4 females which were followed under field conditions 
 for a total of 93 " weevil-days " deposited 489 eggs during that time, or 
 at the rate of 5^ eggs each per day. Where the rate of activity is so 
 great it is probable that the length of the period would be somewhat, 
 but not proportionately, shortened. From many observations made 
 in the field during the beginning of the squaring season it seems prob- 
 able that a rate of 5 eggs a da}' is not far from the average in the field. 
 
 From 21 females of the first generation a laboratory average rate of 
 2^ eggs each daily was obtained. Five females of this generation 
 confined in a cage in the field during the latter part of August for a 
 total of 70 " weevil days" deposited an average of 64- eggs per day. 
 This latter rate is far beyond the actual average rate in the field at 
 that period because of the fact that the weevils can not at that time 
 find enough uninfested squares to lead them to deposit so many eggs, 
 but the possibility remains if only squares enough are present. 
 
 A few words must be said in further explanation of the differences 
 which appear between the field and laboratory results. In the case 
 of the laboratory figures the entire oviposition period of each weevil 
 and the entire number of eggs deposited are taken into the account. 
 As there is a gradual increase in the rate of production of eggs after 
 the beginning of deposition and a gradual decrease from the middle 
 of the period to its end, the general average is much lower than would 
 be that taken at the time of maximum activity. In the case of the 
 field figures a short period only is covered, and all conditions of square 
 supply were such as to stimulate the weevil to its greatest possible 
 activity. 
 
69 
 
 M \ \ I Ml M. 
 
 The daily observations made upon tie- w<-<-\ ils in the laboratory 
 supph a vasl Dumber of observations from which to select maximum 
 figures. Ii has been ^li<»\\n thai under favorable conditions weevils 
 ni;i\ !><■ expected to produce an average of ,; eggs .1 daj for .1 ennsid- 
 erable period of time. Ii is aol surprising, therefore, thai some of I lie 
 maximum figures obtained are very much larger than thai number. 
 A iVw instances only will be taken from among thousands of daily 
 records. 
 
 The highesl record of eggs deposited shows thai -small females 
 deposited together L08 eggs in ;! days, or al the daily rate of 18 i 
 ra<h. This record was made on the 7th, 8th, and '.»ili of June, L903. 
 
 Table XVII. Maximum rate of oviposition. 
 
 Number Days in- 
 of eluded 
 females, inperiod. 
 
 
 Number 
 
 of 
 
 females. 
 
 Days in- 
 cluded 
 inperiod. 
 
 Total 
 eggs de- 
 posited. 
 
 Average 
 per day. 
 
 T 
 
 "> 
 
 3 
 5 
 5 
 
 1 
 2 
 
 108 is. ii 
 76 15. a 
 
 llMI Kin 
 
 11.0 
 
 47 1 1 . s 
 
 i 
 
 1 
 
 •> 
 3 
 5 
 
 2 
 3 
 
 .-> 
 2 
 
 1 
 
 4:< 
 30 
 114 
 54 
 12 
 
 10.8 
 
 10.11 
 11.4 
 9.0 
 
 s.4 
 
 12 
 
 „; 
 
 446 13.5 
 
 13 
 
 13 
 
 283 
 
 9.5 
 
 STIMULATING EFFECT OF ABUNDANCE OF SQUARES [JPON EGG 
 
 DEPOSITION. 
 
 Four actively laying females were confined together upon a few 
 squares from September 22 till October 14, 1902, and during this 
 period they laid a total of 227 eggs, or an average of 2.37 eggs per 
 weevil per day. For the next 13 days these same weevils were isolated 
 and supplied with an abundance of squares. During this shorter 
 period they laid 2o<'> eggs, or 4.54 eggs per female daily. 
 
 Taking equal periods as near together as possible and using these 
 same weevils, there were deposited in V-\ days upon a few squares 
 1 1 1 eggs, or 2.74 eggs per female daily, while during the following 13 
 days, with an abundance of squares, they each deposited 4.54 
 a day. 
 
 These figures are the more striking because the stimulation was 
 plainly shown in spite of the general tendency to lay fewer eggs as the 
 weevils grow older and as the average temperature becomes lower. 
 
 RELATION OF WARTS TO OVIPOSITION. 
 
 When the general relation of the warts to the formation of egg 
 punctures was first recognized, an investigation was undertaken to 
 
 determine, if possible, in what proportion of cases the warts could be 
 1 raced directly to egg or feeding punctures. For this purpose a large 
 number of squares, most of which had warts, was picked from plants 
 
70 
 
 in the field and carefully examined in the laboratory. Notes were 
 made especially upon the following points: The number of warts, the 
 number of punctures obviously made for feeding only, the number 
 of special egg punctures, and the numbers of eggs, larvae, and pupae 
 found. Only those excrescences were counted as warts which showed 
 a positive elevation, and, as was expected, many eggs were found 
 which had not been deposited long enough for a wart to have formed. 
 Out of the 105 squares examined, 20 showed no warts, while the 
 remaining 79 squares had 92 warts. In tracing the connection of 
 these 92 warts it was found that 77 at least, or almost 84 per cent of 
 the total, resulted from egg punctures. The other 15 warts, or 16 per 
 cent, were assigned to feeding punctures, though some of these may 
 possibly have been egg punctures in which decay had concealed all 
 trace of the eggs or small larvae. One-half of the eggs found were 
 in punctures closed by developed warts, and it is likely that most of 
 the other half were of too recent deposition for warts to have formed. 
 Three-fourths of the larvae found in this lot were in punctures which 
 had been overgrown by warts. 
 
 In another series of 35 older squares, 38 warts and 32 eggs, larvae, 
 and pupae were found. This series also shows that at least 84 per cent 
 of the warts resulted from egg punctures. The conclusion seems jus- 
 tified, therefore, that warts may be considered as the most conspicu- 
 ous external indication of the presence of the weevil in some stage 
 within the square. 
 
 It should be noted in connection with warts that feeding frequently, 
 and oviposition more rarely, is followed by a peculiar gelatinization of 
 the injured portion of the square. This condition spreads, and the 
 change produces a considerable internal pressure, so that the square 
 becomes distorted and bulges, especially at the place where the punc- 
 ture was made. The bulging portion often resembles somewhat a 
 wart formation, but its real nature is very different. In many cases 
 the gelatinized condition appears to have caused the death of the 
 young larvae, either by the pressure or by the abnormal condition of 
 the food supply. In a large number of cases, however, this condi- 
 tion undoubtedly results from what were feeding injuries only. 
 
 EFFECTS OF OVIPOSITION UPON SQUARES. 
 
 The method of recording the progress of injury to each square, as 
 was done in the field cages, has furnished much data upon a number 
 of important points. Among these the two of most importance are, 
 in order of their occurrence, the flaring and the falling of the square. 
 
 FLARING. 
 
 The flaring of squares (PL X, fig. 42) is one of the most apparent 
 signs of weevil presence, although by no means an invariable accom- 
 paniment, as it is usually thought to be. Squares flare in nearly as 
 
71 
 
 large a proportion of oases from adult feeding Injur} alone as from 
 Larval injury within. \\\\ Injury severe enough to cause the falling 
 of the square is as Liable to cause Raring as is i be Lan a of I be weeviL 
 Flaring results from an unhealthy condition, whatever ma} be the 
 
 cause, and is frequently to be seen in squares which arc about i<> be 
 shed, though they bave never been injured by anj insert. Eowever, 
 flaring bas come to be popularly associated with weevil injury, and 
 must therefore 1><' quite fully considered. 
 
 When resulting from weevil injury, flaring does oot begin, asa rule, 
 immediately after the injury, but only within from one to three days 
 of the time when the square will be ready to fall. In especially 
 severe cases of feeding injury, paring often results in Less than twenty- 
 four hours. Occasionally the growth of the square overcomes the 
 injury from feeding and the involucre, after having Mated, again 
 closes up and the square continues its normal development as though 
 uninjured, and forms a perfect boll. More frequently -the square 
 gradually loses its healthy green, becoming a sickly yellow in color, 
 and falls in a short time. 
 
 When injured by the feeding of a young larva as the direct result 
 of successful oviposit ion, flaring has been found in an average of J 30 
 cases to bake place in almost exactly 7 days from the deposition of 
 the egg. These observations cover the season from June to Septem- 
 ber, when the developmental period averages about 19 days. Fully 
 one-third of the weevil's full development has, therefore, taken place 
 before flaring results. 
 
 FALLING. 
 
 Squares which flare because of injury from larval feeding within 
 always fall, except the small percentage which, though entirely cut 
 off from all vital connection with the plant, still remain hanging 
 thereon by a small strip of bark and gradually become dry ami brown 
 upon the plant. Falling is but the natural final consequence of injury 
 or disease (PI. XII, fig. 46). Whatever its cause, it is brought 
 about in exactly the same way as the shedding of leaves by the plant 
 in the fall, by the formation of an absciss layer of corky tissue cutting 
 off the fibro- vascular bundles supplying nourishment to the square. 
 The exact location of the cork area is to be seen at the scar left by 
 every fallen square. 
 
 In 539 cases definitely noted between June and September, 1003, 
 the average lime from egg deposition to the falling of the square was 
 9.6 days. For this same period full development required an average 
 of 19 days, so that falling occurred at the middle point in the weevil's 
 development. From a comparison of the time of flaring with that of 
 falling it is seen that the interval between these two points averages 
 about 2.5 days. In late fall the time between oviposition and falling, 
 as recorded in 21 cases, w T as found to be about 10 days. 
 
72 
 
 PERIOD OF OVIPOSITION. 
 
 With llir exception of hibernated weevils, it appears that oviposi- 
 tion begins with most females within a week after they begin to feed 
 ami continues uninterruptedly until shortly before death. While 
 females frequently deposit their last eggs during the last day of their 
 life, a period of a few days usually intervenes between the cessation 
 <;l* oviposit ion and death. 
 
 In the case of 52 hibernated females the actual period of oviposition 
 averaged about 48 days, the maximum being fully 02 days. 
 
 In an average made with 21 females of the first generation the 
 actual period was almost 75 daj*s, the maximum period being 113 days. 
 
 The average period for the females of the first two generations 
 appears to be longer than that for any other. In the third generation 
 the average period for 11 females was 58 days, the maximum being 00 
 days, and in the fifth generation for 5 females the period averaged 48 
 days, with the maximum only 02. 
 
 The approach of cold weather cuts short the activity of the weevils, 
 which become adult after the middle of August, thereby decreasing 
 the length of their oviposition period. Weevils which pass through 
 the winter actually live longest, but as it must take more or less vital- 
 it}* to pass through the long hibernation period their activity in the 
 spring is thereby lessened. 
 
 The weighted, average period of oviposition of the 80 females here 
 mentioned is 55.0 da}*s. 
 
 DOES PARTHENOGENESIS OCCUR? 
 
 To test the possibility of weevils reproducing parthenogenetically, 
 12 individuals were isolated from the very beginning of their adult 
 life. Each beetle was supplied daily with fresh, clean squares and 
 careful watch was kept for eggs. The first noticeable point was that 
 no eggs were found till the weevils were about twice as old as females 
 usually are when they deposit their first eggs. After the}* began to 
 oviposit, it was found that a very small proportion of the eggs were 
 deposited in the usual manner within sealed cavities in the squares, 
 but nearly all of them had been left on the surface, usually near to 
 the opening to an empty egg puncture. This same habit was shown 
 by a number of females, and so can not be ascribed to the possible 
 physical weakness of the individuals tested. The number of eggs 
 deposited was unusually small, and those few placed in sealed cavities 
 failed to hatch. After somewhat more than a month had been passed 
 in isolation, one pair was mated to see if .any change in the manner of 
 oviposition would result. The very next eggs deposited by this fer- 
 tilized female were placed in the square and the cavity sealed up in 
 the usual maimer, showing that her infertile condition had been the 
 cause of her abnormal manner of oviposition. 
 
 A much more extensive series of experiments along this line is 
 desirable and will be made. 
 
n 
 
 DEVELOPMENT. 
 
 PERCENTAGE OF WEEVILS DEVELOPED FROM INFESTED 
 
 SQUARES. 
 
 During the season of L902 part of the many squares gathered in 
 Infested fields for the breeding of weevils were followed to Learn some- 
 thing of the percentage which produced normal adults. No exami- 
 nation was made for those nol yielding a weevil. The decay of the 
 square during the period from its falling to tin- maximum time that 
 must be allowed for weevils to escape normally so obliterates any 
 small amount of work by a Larva that it is difficult even with exami- 
 nation t<> determine accurately the number of dead small Larvae. 
 
 Table XVIII. — Percentage of weevils from infested squares. 
 
 Locality. 
 
 Approximate dab . 
 
 Number 
 
 of 
 squares. 
 
 Number 
 weevils. 
 
 Percenl 
 age ot 
 squares 
 producing 
 weevils. 
 
 Victoria, Tex 
 
 um. 
 
 July t<> August 
 
 1,125 
 
 381 
 
 334 
 368 
 
 360 
 
 ins 
 
 106 
 365 
 192 
 
 33.0 
 
 
 
 Victoria, Tex 
 
 1903. 
 June 
 
 82.0 
 
 Do 
 
 June to August 
 
 August to September 
 
 41.il 
 
 Do.. 
 
 52 '1 
 
 
 
 Total. _._ 
 
 3,087 
 
 1,121 
 
 :*>. 3 
 
 
 
 
 It seems safe to conclude that throughout the season fully one-1 hird 
 of the squares which fall after receiving weevil injury may be expected 
 to produce weevils. 
 
 DEVELOPMENT OF WEEVILS IN SQUARES WHICH NEVER FALL. 
 
 It is generally true that squares seriously injured by the weevil 
 sooner or later fall to the ground. Some plants, however, shed the 
 injured squares more readily than do others. It seems to he a mat- 
 ter of individual variation rather than a varietal character. Thus 
 occasional plants retain a large proportion of their infested squares, 
 which hang by the very tip of the base of the stem. Normally the 
 squares are shed because of the formation of an absciss layer of corky 
 tissue across their junction with the stem. In the ease of the squares 
 which remain hanging the formation of this layer seems to be incom- 
 plete, or else it becomes formed in an unusual plane, so thai while the 
 square is effectualh' cut off, it merely falls over and hangs by a bit of 
 bark at its tip (PI. XII, tig. 47). In this position it dries thoroughly 
 and becomes of a dark-brown color. Plants showing 6 or 8 of these 
 dried brown squares are quite common in infested fields. Although 
 exposed to complete drying and the direct rays of the sun, the larva' 
 within are not all destroyed. This peculiarity reminds one strongly 
 of the European Anthonomus pomorum the work of which in cans- 
 
74 
 
 ing apple buds to hang dead upon the trees has caused the common 
 name of "Brenner" to be applied to it. 
 
 At intervals during the summer of 1903 such dried squares and 
 small dried bolls were picked for careful examination in the labora- 
 tory, the condition of 342 being recorded, with the following results: 
 
 Adults present 2, escaped 23; pupse alive 29, dead 2; larvae alive 85, 
 dead 47; parasites present 44, escaped 6. Sixty-three squares which 
 failed to show weevil work and 42 small dried bolls from which the 
 corollas had fallen were probably destroyed largely by the feeding of 
 the weevils. Taking the total number of squares and bolls examined 
 as the basis of computation, it appears that 69.3 per cent of them 
 showed weevils present in some stage. Of the immature stages, 30 
 per cent were dead, 14.6 per cent having been parasitized. It seems 
 a conservative estimate therefore to say that fully one-third of these 
 exposed dried squares may be expected to produce adults. Consider- 
 ing the exposed condition of such squares this seems to be a very 
 high percentage. 
 
 The season of 1903 was not as hot at Victoria as was that of 1902, 
 and the lower temperature prevailing may have favored the develop- 
 ment of a larger proportion of the weevils in these squares than would 
 normally emerge. The maximum temperature reached in 1902 was 
 104.3° F., while in 1903 the maximum was only 97.5° F. No examina- 
 tions of this subject were made in 1902, and therefore no positive 
 comparisons can be drawn. The observations made, however, cer- 
 tainly show that a complete drying of the square does not necessarily 
 destroy the larva, and that a square may undergo far more exposure 
 to direct sunshine than had been supposed possible without causing 
 the death of the larva or pupa within. 
 
 LENGTH OF THE LIFE CYCLE. 
 
 This question has been studied carefully, both in the laboratory 
 and in the field. Most of the observations made in 1902 were in the 
 laboratory, while those of 1903 were in the field. 
 
 In the laboratory uninfested squares were exposed to active weevils 
 for oviposition, and the supply of clean squares was renewed each 
 day. The beginning of the cycle was thus known to within a few 
 hours. The squares with eggs were carefully kept and the date of 
 emergence of each adult was then noted. To the period thus found 
 must be added the time intervening between the leaving of the square 
 and the deposition of the first eggs. This gives the length of the life 
 cycle. The material upon which these observations were made was 
 necessarily other than that used in determining the length of the 
 various stages. The period in bolls is far different from that in 
 squares. The figures here given refer to squares. 
 
T u:i.i XIX. /.< ngih of lift oycl 
 
 
 i ibsen al 
 
 
 Time in 
 develo 
 
 ieriod of 
 
 imiciit . 
 Average. 
 
 A\ nmgn 1 \mt 
 
 Temporal ore 
 
 Period covered. 
 
 N 1 1 ii i 
 
 bar 
 
 
 A. lull to 
 
 ovipo i 
 
 t i * hi. 
 
 Lenfth 
 
 .,i 
 cycle. 
 
 A rerage 
 
 effort 
 
 i\ e. 
 
 Total 
 
 A i 
 
 S«- 
 
 MOB 
 goal in to September :*> 
 ttomber 16 to < October 18 
 bober > bo November 10 
 
 90 
 
 BOB 
 
 08 
 
 100 
 LOO 
 
 Day 
 
 Hi is 
 18 85 
 n 88 
 
 l- 88 
 L8 88 
 
 Day*. 
 
 S. i 
 17.B 
 
 18. 8 
 L9.0 
 
 Day*. 
 
 7.(1 
 8.0 
 
 :.. 8 
 
 Day 
 
 [8 i 
 
 -I i 
 
 84 
 
 ii 
 
 88.0 
 88.1 
 
 i 
 904 i 
 
 PJ 
 
 ttO& 
 
 •id. first generation: 
 
 June 4 t.> Jnly r» 
 
 August 80 to September 88 
 
 Total 
 
 704 - 
 
 m i 
 
 
 747 
 
 10-2(5 
 
 
 
 
 
 \Y 
 
 
 17.8 
 
 0.8 
 
 84.0 
 
 84.1 
 
 -i- I 
 
 
 
 
 
 
 These observations eover the season from June 1 to November L6. 
 Reproduction undoubtedly begins somewhat earlier and continues 
 
 later in the average season at Victoria, but any differences which 
 might be found at the extremes would not materially affect the Loca- 
 tion of the mean in so large a series. The influence of varying tem- 
 perature during the same period but in different seasons is clearly 
 seen by a comparison of the figures for August 10 to September 30, 
 1902, with those for August 20 to September 28, 1903. The period for 
 1902 was exceptionally warm, as shown by the high average effective 
 temperature, while in 1903 it was decidedly cooler, the difference 
 averaging 8° F. ; consequently the average length of the cj T cle was 
 fully six days greater in 1903 than in 1902 at the same period. 
 
 Determinations of the length of the life cycle in bolls have been 
 made in only a few instances. In 7 cases between August 15 and 
 November 11, 1903, the average time required from the deposition of 
 the egg to the escape of the adult from the opening boll was Gl days. 
 The average effective temperature for the period was 31.7° F., and 
 the average total effective temperature required for development in 
 bolls was therefore 1,933.7° F., or nearly two and one-half times as 
 much as in squares. Several larvae often develop within a single boll 
 (PI. XI, fig. 43). They appear to remain in the larval stage until the 
 boll becomes sufficiently mature or so severely injured as to begin to 
 dry and crack open. When this condition of the boll is reached, pupa- 
 tion takes place, and by the time the spreading of the carpels is suffi- 
 cient to permit the escape of the weevils they have become adult. 
 
 BROODS OR GENERATIONS. 
 
 The term "brood" can hardly be applied in its usual sense to the 
 generations of the weevil, as was pointed out by Doctor Howard in 
 the first circulars of the Division dealing with the problem. For sev- 
 eral reasons no line of distinction can be drawn between the genera- 
 tions at any season of the year, not even between hibernated weevils 
 
76 
 
 and the adults of the lirsi generation. As lias been shown, Hie aver- 
 age period of oviposit ion among hibernated females is in some cases 
 fully ;> months, while il averages 48 days. The length of the full 
 life cycle for the lirsi generation, as shown in Table XIX, is 24 days, 
 and as the time for the second generation would be slightly less, it is 
 evident that the first eggs for the third generation will he deposited 
 at the same time as those for the middle of the second generation, 
 and also with the very last of the eggs deposited by hibernated 
 females for the first generation. The great overlapping of genera- 
 tions thus produced prohibits the application of any of the common 
 methods of ascertaining their limits. The complexity indicated for 
 the first three generations becomes still further increased as the season 
 advances, so that in October, for example, a weevil taken in the field 
 might possibly belong to any one of six generations. Length of life 
 and the period of reproductive activity are important factors in deter- 
 mining the average number of generations. Periods of greatest 
 abundance can not be regarded as giving any reliable information 
 upon this point, since the number of weevils developed soon comes to 
 depend largely upon the suppl} 7 of squares. 
 
 In the case of the boll weevil, therefore, the information upon the 
 number of generations must be drawn from laboratory sources. Many 
 of the hibernated weevils continue to deposit eggs until the middle of 
 'July, and some are active for fully a month longer. In 1903 the last 
 eggs from hibernated weevils were deposited on August 27. In the 
 course of breeding experiments made in 1902 it was found that many 
 weevils which had become adult about the 1st of August would con- 
 tinue to deposit eggs until the latter part of November. Considering 
 the longest-lived weevils and their last-laid eggs, therefore, it is easily 
 possible for two generations to span the entire year. The weevils 
 developing after the middle of November may go into hibernation, 
 and from their last-deposited eggs produce weevils whose last off- 
 spring will be ready for successful hibernation again. This conclu- 
 sion is based upon actual demonstration. 
 
 The maximum number of generations will be found by taking the 
 first, instead of the last, deposited eggs in each case. Rather than lay 
 the conclusions open to question by taking the figures found for occa- 
 sional minimum length of the life C3 7 cle, we will take the 24-day 
 period, which has been shown to be the average between June 4 and 
 November 16. Without doubt hibernated females begin their repro- 
 ductive activity in average seasons by Ma} 7 1, and their descendants 
 continue to develop normally until after November 15. Taking the 
 dates mentioned, however, as the average season for the weevils, we 
 find that eight generations, each having the average period of devel- 
 opment, may usually be produced within the year. 
 
 In determining the average number of generations one-third the 
 average period of oviposition should be added to the average life C3 T cle 
 
for each generation." As it has been found that the average poriod of 
 oviposition is about 5 1 days, \n < * must allow 24 days for the develop 
 iiimi of ihr average adult and L8 more days for the female t<» deposit 
 one half her eggs. Forty-two days is therefore about the average 
 Length of a generation; and we ma} thus count on an average oi about 
 ftve generations between May l and December I. In the northern 
 part of the weevil territory, where the season is shorter and the pre- 
 vailing temperature lower, probably only four generations would be 
 (lc\ eloped. 
 
 There is uo basis for the idea that there is a distinct hibernation 
 brood. I'll" activity of the adults and the development of the imma- 
 ture stages is gradually retarded by the decline in temperature until 
 hibernation lime arrives. Most of t he weevils of the firsl i \\<> or three 
 generations have probably died, or then do so, while most of the ad nils 
 of Later generations, having si ill considerable vitality, will go into 
 hibernation. If is certain that every generation preceding may have 
 some direct part in the production of weevils which shall hibernate. 
 All weevils which are still strong and healthy when cold weather comes 
 on may he expected to go into hibernation, so that there can be no 
 special brood for this purpose. 
 
 THERMAL INFLUENCE UPON ACTIVITY AND DEVELOPMENT. 
 
 The influence of temperature has been frequently mentioned as an 
 important point, but it may be more clearly understood by collecting 
 some of the most important observations relating to it. A study of 
 this subject throws much light upon such questions as seasonal and 
 daily activity, the rapidity' of development at various seasons, hiber- 
 nation, and the time of emergence from hibernation. The influence 
 upon development will be first considered. 
 
 « One-third is nearer the correct fraction than one-half, since it hits been found 
 thai weevils deposit considerably more than one-half of their eggs during the first 
 half of their oviposition period. 
 
78 
 
 Table XX. — Thermal influence on development. 
 
 Stage. 
 
 Egg- 
 Larva 
 
 Pupa . 
 
 Entire develop 
 mental period . . 
 
 Number 
 of obser- 
 vations. 
 
 KIT 
 36 
 
 196 
 
 15 
 
 15 
 
 161 
 
 81 
 
 167 
 
 29 
 
 4 
 
 305 
 66 
 
 100 
 
 185 
 
 Period. 
 
 L902 
 
 Sept. 4 to Oct, 3 
 
 Oct. 7 to Nov. 13_... 
 Nov. 24 to Dec. 15... 
 
 Sept, 6 to Oct. 5 
 
 Sept, 26 to Oct. 21... 
 Nov. 11 to Dec. 12... 
 
 July 6 to 31 
 
 Sept, 15 to Oct. 3 
 
 Sept. 24 to Oct. 28... 
 
 Nov. 2tol3 
 
 Dec.2to29 
 
 Aug. 10 to Sept. 30.. 
 Sept. 16 to Oct. 15... 
 Oct. 8 to Nov. 16.... 
 
 1903 
 
 June 4 to July 15 
 
 Aug. 20 to Sept. 28.. 
 
 Average 
 
 time for 
 
 stage. 
 
 Da vs. 
 3- 
 4+ 
 11.0 
 
 7.5 
 
 9.5 
 
 25.0 
 
 3. 5 
 5.2 
 6.0 
 7.6 
 14.5 
 
 13.4 
 17.5 
 20.3 
 
 18.3 
 19.0 
 
 Effective tempera- 
 ture. 
 
 Average. Total 
 
 38. G 
 30. 
 
 19.0 
 
 35.7 
 30.6 
 19.5 
 
 39.65 
 36.0 
 31.1 
 26.2 
 
 18.5 
 
 41.0 
 33.6 
 29.5 
 
 32.0 
 33.1 
 
 F. 
 
 114.0 
 
 126.0 
 
 2«nu) 
 
 267.7 
 280.7 
 
 487.5 
 
 138.8 
 187.2 
 186.6 
 199.1 
 268.2 
 
 549.4 
 
 588.0 
 598.8 
 
 585.6 
 628.9 
 
 SUMMARY OF THE PRECEDING TABLE. 
 
 Stage. 
 
 Egg -- - 
 
 Larva 
 
 Pupa _ 
 
 Total development 
 
 Observations on entire period 
 
 Total 
 observa- 
 tions. 
 
 528 
 225 
 442 
 
 1.195 
 752 
 
 Average Average Total 
 period effective effective 
 for tempera- tempera- 
 stage, ture ture. 
 
 3.75 
 
 8.8 
 
 5.1 
 
 17.65 
 17.7 
 
 F. 
 35.1 
 34.3 
 34.7 
 
 34.8 
 33.9 
 
 F. 
 
 141.6 
 301.8 
 177.0 
 
 614.2 
 600.0 
 
 In studying the influence of temperature on development the figures 
 upon the separate stages serve best, as they give the widest range. In 
 each stage it may be seen that the maximum time is nearly, if not 
 quite, four times the minimum, while the average effective tempera- 
 ture difference is in the inverse order, but about 2 to 1. In com- 
 paring the minimum and maximum total effective temperatures, it 
 appears that when the average temperature is lowest the total heat 
 required to complete the development of the stage is nearly twice as 
 great as when the average temperature is highest. The length of the 
 developmental period is therefore not exactly inversely proportional 
 to the change in temperature. The retarding influence of decreasing 
 temperature appears to affect each of the immature stages in very 
 nearly the same degree. The total effective temperature required 
 forms a specific constant, which is fairly uniform for average effective 
 temperatures of between 30° and 40° F. These temperatures would, 
 during most seasons, prevail from June to October, inclusive. As the 
 average effective temperature falls below 25° F., however, there 
 results a great and disproportionate retardation in the development. 
 The reason for this difference may lie in the fact that when tempera- 
 
T9 
 
 fore is ascending from 32 r. it must attain .1 higher point bo Btarl 
 weevils into activity than that .n which the same weevil will cease 
 activity when the mercury is going down. 
 The observal ions upon the length of the entire developmental period 
 
 were made upon a different Beries of ww\ iK As is clearly shown in 
 the summary given in the Latter pari of the table, the sum of the 
 average lengths of the three stages agrees remarkably closely with 
 the length of tin* entire period as found in the 752 rases observed. 
 'Tins close agreement, readied by entirely different methods, indicates 
 that the series from which the averages are obtained are sufficiently 
 Large to give constant results, and therefore thai the average period 
 of development throughout the season of weevil activity is very close 
 to I s days. 
 
 This thermal influence upon activity in feeding and oviposition may 
 be shown by taking various lots of weevils at intervals through the 
 season. For this purpose the work of LO males and LO females lias 
 been selected, using the Laboratory records for each lot. The time 
 covered is 25 days in each case to secure a fair average, and 25-day 
 intervals separate the lots from eaeli other. The season thus covered 
 begins with June G and ends with November 28, 1903. To make the 
 comparison fair, average conditions as to sex, age, and individual 
 activity must be established, and the records have been selected with 
 these conditions in view. 
 
 Table XXI. — Thermal influence on activity in feeding and ovipositing. 
 
 Xum- Number 
 
 Period. 
 
 Average 
 
 Total. 
 
 Daily average JEffgg*. 
 
 berof of fe- 
 males, males. 
 
 tempera- 
 ture. 
 
 Feeding 
 punc- 
 tures. 
 
 Eggs. 
 
 Feeding 
 punc- 
 tures. 
 
 Eggs. 
 
 Feeding 
 pane- Eggs, 
 cores. 
 
 Hi in 
 10 in 
 
 in id 
 in in 
 
 1903. 
 
 June i» to :-fl> -. 
 
 July 25 to A.ug. l'.i 
 Sept. 14 to Oct. 8.... 
 Nov. ;J to 27 
 
 ° F. 
 38. 1 
 36. 5 
 38.7 
 84.6 
 
 8,189 
 8,325 
 
 l.ran 
 900 
 
 794 
 
 1,061 
 669 
 817 
 
 87.6 
 93.0 
 61.6 
 36.0 
 
 31.8 
 
 42.4 
 2*>.4 
 
 8.7 
 
 4.4 
 4.7 
 3.1 
 L.8 
 
 3.2 
 
 4.2 
 2.6 
 0.9 
 
 
 
 
 The average number of daily feeding punctures is reckoned for both 
 sexes alike. Though the females made more than half, the propor- 
 tions can not be positively separated, and it would make no difference 
 if we could do so. It is noticeable that the period of greatest activity 
 comes in midsummer, With the first, second, and third generations 
 actively at work. Hibernated weevils working in June show greater 
 activity than do the mixed generations which occur together in Septem- 
 ber and October, though the temperature does not greatly vary. In 
 November, with a marked fall in temperature, there is a corresponding 
 decrease in work, but especially is this noticeable in egii; deposition. 
 It appears that at this season and later on the weevils are mostly eat- 
 ing to live until it becomes cold enough for them to hibernate, 
 
80 
 
 LABORATORY EXPERIMENT IN EFFECT OF TEMPERATURE UPON 
 LOCOMOTIVE ACTIVITY. 
 
 The experiments here given were performed by Dr. A. W\ Morrill. 
 In the absence of apparatus especially designed for such work, use 
 was made of a very simple device, constructed as follows: 
 
 A thermometer was passed through a cork and inclosed in a test 
 tube, which in turn was placed within a hydrometer cylinder of snl- 
 Bcienl depth to inclose it (PL XIII, fig. 49). 
 
 Weevils were inclosed in the test tube with the thermometer, and 
 the temperature of the cylinder varied either by heating gently or by 
 the use of ice water. Starting with the thermometer at 04° F., the 10 
 weevils inclosed were found to move slowly, half of them being quiet. 
 As the temperature was gradually raised the activity of the weevils 
 increased up to 105° F. When the temperature reached 95° F., or 
 over, the weevils were running up and down the tube. By filling the 
 cylinder with cold water the temperature was lowered to 86° F.. a1 
 which point the weevils began to cluster at the top on the cork and 
 were crawling slowly. By the addition of ice in the cylinder the tem- 
 perature was lowered to 59° F., at which point 5 weevils were sprawl- 
 ing on the bottom of the test tube or clinging to one another, 4 were 
 clustered on the stopper, while 1 was slowly crawling downward. At 
 50° F. 6 weevils at the bottom showed slight signs of life and 1 was 
 crawling slowly. At 45.5° F. slight signs of life were still shown, 
 while at 40° F. occasional movements only were noted. Upon the tem- 
 perature being raised weevils began crawling as 50° F. was passed, 
 and at 64° F. all had left the bottom and were crawling upward. 
 Some recovered much more quickly than did others. 
 
 The temperature was again lowered, this time by the use of salt with 
 ice. All movement ceased at 37° F. The cooling, however, was con- 
 tinued to 33° F., after which it was slowly raised to 42° F., at which 
 point movements began. 
 
 In a general way these results agree quite closely with outdoor 
 observations. 
 
 HIBERNATION. 
 
 Fven after frosts have blackened the foliage and squares and 
 entirely checked the growth of the plant, some weevils can be found 
 moving in a cotton field upon warm days. Weevils which are old and 
 nearly exhausted die as the cold weather comes on. Their vitality 
 has been expended in other ways and they do not survive the winter. 
 Those which are still vigorous and strong will continue to feed a little, 
 and females will occasional^ deposit eggs so long as cotton remains 
 green. In southern Texas larvre and pupa? which are in squares when 
 frost comes are not killed thereb} 7 , but slowly finish their development 
 if the weather is warm enough for any activity, and the young adults 
 thus developed may live the winter through without feeding. As 
 

 Plati XIII. 
 
 -iv 
 
 Favorable and Unfan 
 
 vBLE UONDI 
 
 for Weevil Acti 
 
 Fig. 49, Device used to test effect of temperature upon weevil activity, one-third natural size; 
 fig. 50, comparison of pilosity on "King" (at left) and "Mit Afifi" (at right) stems, natural 
 size: Hlt. 51, locality found very favorable to hibernation of many weevils. (Original, i 
 

 XIV. 
 
 £ vv>\ 
 
 Insects Often Mistaken for Boll Weevil. 
 
 Fitrs. 52, 53, Mexican cotton boll-weevil (Antlionomus grandis), much enlarged (redrawn, after 
 Hunter); fig. 54, Lixussp., enlarged :>.; times (original); fig. 55, acorn weevil {Balaninus uni- 
 formU auct.): a, female, dorsal view; b, same, lateral view: c, head, snout, and antenna of 
 male— all enlarged J times (from Chittenden, unpublished); fig. 56, apple curculio (Cocco- 
 torus scuteUaris), enlarged (from Insect Life); fig. 57, plum gouger ( Anthonomus prunicida), 
 enlarged (from Insect Life); fig. 58, Desmoris scapalis, enlarged (original). 
 
81 
 
 observed i»\ Mr, E. A. Schwarz in the winter of L901 2, weevils may 
 pass the winter in either larval, pupal, or adull stages, bnl the last 
 earned is by far the most common stage. 
 
 Ii is likely thai a large part of the weevils found in the squares and 
 bolls during the first pari <>f the winter will be in the Larval stage, 
 while, owing to i he slow development which takes place, a larger per- 
 centage of adults will be found toward Bpring. Mr. J. I). Mitchell, 
 of Victoria, Tex., took a number of live larv®, pupse, and adults from 
 bolls in a Held in that Locality <>n December 26, L 903, after "two hard 
 frosts and one freeze." Two weeks Later, from afield al the same 
 locality, after three hard frosts and two freezes, he look another lol 
 of live specimens in these three stages. In the Latter case the bolls 
 examined were on stalks which had been plowed oul two weeks before 
 and were ready for burning al the time examined. Mr. Mitchell, who 
 is an excellent and reliable observer, writes: kk ()n December 26, there 
 was still some sap in the cotton stalks," and on January 10, when the 
 second examination was made, "there was absolutely none." "The 
 Larvae seem to thrive and arrive at perfection in the dead and dried 
 bolls. A frost or freeze at :5<> F. does not hurt the larva' or pupae in 
 dead bolls in the field." As the two lots, taken together with four others 
 sent January 17, 31, and February? and 14, 1904, include 197 specimens 
 (23 larva 1 , 30 pupae, and 144 adults) it is evident that Large numbers of 
 weevils go into the winter in the immature stages, and there is every 
 probability that, in the southern part of the State at least, many of 
 them live and mature, emerging in the spring. It may be that this 
 gradual maturity of the hibernated weevils is one of the reasons why 
 they emerge so irregularly from their winter quarters. Not all wee- 
 vils go into hibernation at the same time, but as the mean average 
 temperature falls to between 55°and60°F. they gradually cease feed- 
 ing, and, numbed and sluggish, they crawl into almost any place 
 which furnishes them some measure of protection from the cold. 
 Hibernating weevils are therefore to be found in many situations in 
 the field. Where the cotton stalks are allowed to stand throughout 
 the winter they furnish the weevils both the means of subsistence late 
 in the fall and an abundance of favorable hibernation places through- 
 out the field. The prospects of successful hibernation are thereby 
 multiplied many times; and, furthermore, the weevils are already 
 distribut d over the field when they first become act ive in the spring. 
 The grass and weeds which almost invariably abound along fence lines 
 are exceedingly favorable to the successful hibernation of many wee- 
 vils, so that it will be found generally true thai the worst line' of 
 infestation in the spring proceeds from the outer edges of the field 
 inward. Where cotton and corn are grown in adjacent fields, or 
 where, as is sometimes the case, the two are more or less mixed in 
 the same held, many weevils find favorable shelter in the husks and 
 stalks of the corn. An especially favored place is said to be in the 
 2 1 7: 1! )— No. 45—04 
 
82 
 
 longitudinal groove in the stalk and within the shelter of the clasping 
 base of the leaf. Perhaps the most favorable of all hibernating con- 
 ditions are to be found among the leaves and rubbish abounding in 
 the edges of timber adjoining cotton fields. From such places the 
 weevils are known to come in large numbers in the spring. The 
 timber fringes present greater difficulties in the way of removing the 
 favorable conditions than do any of the other places mentioned. 
 
 Temperature and available food supply seem to be the most impor- 
 tant factors in determining the time of hibernation. In general, it 
 may be said that many weevils are active so long as their food con- 
 tinues in fit condition to sustain them. Some, however, undoubtedly 
 seek shelter before frosts occur. From numerous observations made 
 in the laboratory, it appears that weevils will starve when deprived of 
 cotton if the mean average temperature continues long above a point 
 somewhere between 60° and 65° F. As the mean average falls below 
 60° hibernation may take jilace successful^. 
 
 It is a very significant fact that of the 240 weevils taken from the 
 field at the middle of December, 1902, and placed in hibernation, 38, 
 or 15 8 per cent, passed the winter successfully, Avhile of the 116 
 weevils adult before November 15, 1903, only 1, or less than 1 per 
 cent, survived. It is evident that the weevils which pass the winter 
 and attack the crop of the following season are among those developed 
 latest in the fall and which, in consequence of that fact, have not 
 exhausted their vitalit}^ by oviposition or any considerable length of 
 active life. 
 
 LENGTH OF HIBERNATION PERIOD. 
 
 As the observations upon this point have all been made at Victoria, 
 Tex., the statements made refer especially to that locality. It must 
 be borne in mind that latitude and altitude, as well as seasonal varia- 
 tions, will influence the limits of this period. In general, however, it 
 may be said that hibernation begins at about the time of the first 
 hard frost, and that it continues until the mean average temperature 
 has been for some time above 60° F. Iri the spring of 1903 weevils 
 left hibernation quarters at Victoria only when the mean average 
 temperature had been for some time at about 68° F. While it is true 
 that weevils if disturbed in hibernation are active at much lower 
 temperatures than this, for some reason they do not leave the shelter 
 of their hibernation places. 
 
 At Victoria, Tex. , the average hibernation season may be said to 
 extend from about December 1 to about April 1, or a period of about 
 1 months. In more northern latitudes hibernation will, as a rule, 
 begin earlier and last later, covering a period of from 4 to 5 months, 
 
88 
 
 APPARENTLY FAVORABLE CONDITIONS FOR HIBERNATION. 
 
 In December, L902, a series of experiments was started to test the 
 influence of various conditions upon the successful hibernation of 
 weevils. Owing bo the writer's absence from Victoria examinations 
 could not be made al intervals, a> would have been desirable. Bui 
 ,ii the middle of April, L903, careful examinations were mad*' to ascer- 
 tain tlif Bhelter in whicb live weevils were found. In the preparation 
 of hibernation jars several inches of dirl was placed al the bottom, 
 and above t li.it a variety of such rubbish as was thought might 
 tempt theweevilsto Bhelter. Dead banana leaves, hay, cotton leaves, 
 dry bolls, squares, etc., were among the things used as rubbish. As 
 several of these were placed in each jar the weevils had an oppor- 
 tunity to choose their shelter. Among the 39 which lived through 
 the winter, 19 were found in the banana Leaves, 7 in hay, 5 in dry 
 cm ion leaves, I were buried in dirt, 3 were on the surface of the 
 soil, and I wa> hiding in an open boll. It appears, therefore, that 31, 
 o! 80 per cent of the 39 live weevils, were found in what may be 
 termed "leaf rubbish." It was noted also that 25 of the survivors 
 passed the winter out of doors in various locations, while 13 were 
 under shelter indoors. Of the weevils placed out of doors all but 
 one lot were protected from the rain. The 15 weevils contained in 
 the jar which became wet all died, while but few of the jars which 
 were dry failed to show a live weevil in the spring. Leaf rubbish and 
 dryness appear to be favorable factors in successful hibernation. 
 
 PERCENTAGE OF WEEVILS HIBERNATING SUCCESSFULLY. 
 
 Naturally the percentage of weevils living through the winter will 
 depend largely upon favorable climatic conditions and the accessibil- 
 ity of suitable shelter. It would be utterly impossible to determine 
 this question under actual outdoor conditions, and our inferences 
 must be drawn solely from percentages found to survive under cage 
 conditions. In the laboratory tests referred to in the preceding topic 
 356 weevils were used. Of these, 240 were brought from the fields at 
 the middle of December, 1902. Among these weevils, 38, or 15.8 per 
 cent, survived. The remaining 116 weevils were all adult after Sep- 
 tember 25, 1902, and had been kept under observation in the labora- 
 tory. ( )ne single weevil, adult November 12, was the sole survivor of 
 this lot. Since the weevils brought from the fields in the middle of 
 December would be a correct average of those entering hibernating 
 conditions, we may disregard the laboratory specimens in drawing 
 our conclusions. The conditions offered would seem to have been 
 favorable, and when this is the case out of doors it appears that about 
 one in six of weevils found in the field at hibernation time may pass 
 the winter successful^. This seems a very high percentage, but 
 when we consider the numbers of hibernating weevils often occurring 
 
84 
 
 upon young cotton in the spring it seems not improbable that during 
 favorable seasons something like this percentage of the weevils find- 
 ing favorable shelter will live. Of course, the percentage finding 
 favorable shelter will be extremely variable, and it is in reducing the 
 number and accessibility of favorable locations that the cotton planter 
 has one of his very best opportunities to effect the destruction of a 
 multitude of weevils, and thus greatly reduce the number which will 
 emerge from hibernation and attack the crop of the following season. 
 With shelter removed, cold and changeable weather will inevitably 
 destroy many, and, in fact, most, of the weevils which would other- 
 wise survive. 
 
 SEASONAL HISTORY. 
 EMERGENCE FROM HIBERNATION. 
 
 Emergence depends largely, as has been already shown, upon the 
 mean average temperature prevailing. The presence of food does 
 not seem to affect it. In the season of 1903 for one month preceding 
 the emergence of weevils at Victoria the mean average temperature 
 was 65.4° F. For the first two weeks of April it averaged 68.4° F. 
 Weevils left their winter quarters from the middle to the last of 
 April. While the mean average temperature for May was nearly o~ 
 lower than the temperature prevailing at the time of emergence, 
 weevils remained actively at work in the fields. In the fall also 
 weevils remained at work at a lower temperature than that which 
 seems to be necessary to draw them from their winter quarters. The 
 reason for this fact is not apparent, but it is certain that once having 
 left hibernation weevils will remain active at considerably lower tem- 
 peratures. If the temperature becomes too low they remain quiet 
 without taking food for long periods of time. If taken from their 
 winter quarters weevils will be found active at ordinary day tempera- 
 tures long before they would normally venture from their hiding 
 places of their own accord. Weevils thus removed have been kept 
 for a month without food or water, and they then assumed their 
 normal activities when food was supplied to them. 
 
 After considerable search at San Diego in the spring of 1895, on 
 April -7 Mr. Schwarz found the first specimens working upon seppa 
 plants from roots which were then 2- years old. As the weevils first 
 appeared in that locality in August, 1894, the number of hibernat- 
 ing weevils could not have been as great as in succeeding years, 
 and consequently in the spring of 1895 hibernated specimens were 
 "exceedingly rare." At Victoria, Tex., in the spring of 1902, Mr. 
 Schwarz found the first Aveevils working upon volunteer plants on April 
 15. In the same locality the writer found, in 1903, that weevils left 
 their winter quarters between April 10 and May 1. Evidence was 
 found indicating that in some fields they began to move as early as 
 March 28. At Calvert, Tex., also in 1903, Mr. Harris found the first 
 
weevils working on cotton on April L2. At Victoria, in L904, weevils 
 \N«it' found in numbers apon seppa plants <>n March 11 and they 
 were found moving in the Held ai intervals throughoul the winter. 
 From these observations it appears that normal emergence takes 
 
 place usually some lime in April, whether the first Or the last of the 
 
 month depending largely upon the earliness of the season. Further- 
 more, the emergence of the first weevils may lake place from two to 
 
 four weeks before that of the last. In this fact lies one of the two 
 
 great obstacles which prevent the successful application of poisons 
 to the early cotton as a means of (lest roying the weevils. The second 
 
 obstacle Is explained on pages 41-43. 
 
 Owing to the empty condition of the alimentary canal, hibernated 
 weevils are able to fly with ease, and this they must do in their search 
 
 for food. Doubtless many perish soon after emergence, even if they 
 find food which many others never succeed in reaching. 
 
 APPARENT DEPENDENCE OF REPRODUCTION UPON FOOD 
 03TAINED FROM SQUARES. 
 
 During the fall of 1002 a series of experiments, lasting for 12 weeks, 
 was made to determine the length of life of weevils fed solely upon 
 leaves. In one lot, consisting of 9 males and 8 females, the average 
 length of life of the females was 25 days, while that of the males was 
 30 days. Though this period far exceeded the normal time usually 
 passed between the emergence of adults and the beginning of egg 
 deposition, no eggs were found. Dissection of the females which 
 lived Longest showed that their ovaries were still in latent condi- 
 tion, though the weevils were then 81 days old. Few instances of 
 copulation were observed among weevils fed upon leaves alone, and 
 among nearly 70 weevils which were thus tested, no eggs were ever 
 deposited. After a period of 3 weeks upon leaves, 11 weevils were 
 transferred to squares. Females in this lot began to lay in 4 days, 
 and 4 of them deposited 323 eggs in an average time of 20 days. The 
 conclusion seems plain that so long as leaves alone are fed upon 
 eggs do not develop, while a diet of squares leads to the development 
 of eggs in about 4 days. It is worthy of note that the interval 
 between t he first feeding upon squares and the deposition of the first 
 eggs is almost the same with these weevils taken in middle life as 
 with weevils which have just emerged. 
 
 An examination of hibernated females taken in the spring of 1903, 
 whicli had fed for G weeks upon cotton leaves, showed that their 
 ovaries were still latent. Copulation was rarely observed among 
 hibernated weevils until after squares had been given them. In a few 
 days after feeding upon squares, mating and oviposition began. The 
 average period was from 3 to 5 days, and having once begun, ovipo- 
 sition continued regularly. 
 
 It has been found that food passes the alimentary canal in less than 
 
86 
 
 24 hours. Assimilation, therefore, must he very rapid. It is evident 
 that while leaves will sustain life certain nutritive elements found 
 only in squares are essential in the production of eggs. 
 
 Upon dissecting weevils just taken from hibernation it was found 
 that females contained no developed eggs, but that their ovaries were 
 in an inactive condition, similar to those of females which had fed for 
 months entirely upon leaves during the previous fall. Upon examin- 
 ing females taken from seppa cotton later in the spring, but before 
 squares had appeared, it was found that they also were in similar 
 condition. This was also true of females kept in the laboratory from 
 the time of emergence from hibernation until squares became abund- 
 ant, with only leaves for food. It seems peculiar that upon a purely 
 leaf diet eggs are not developed, but all observations made indicate 
 that this is the case. It can not be said definitely whether the females 
 examined had been fertilized, but it is certain that they were not 
 ready to deposit eggs. 
 
 PROGRESS OF INFESTATION IN FIELDS. 
 
 From among the many notes made upon this point the results of 
 the study of two fields are here p resented. The first field, consisting 
 of about 15 acres, had been planted in cotton for several years and 
 was closely surrounded by other cotton fields. The second field of 
 35 acres was upon newly broken land and situated in a comparatively 
 isolated location. 
 
 Examinations were made frequently to determine approximately the 
 percentage of infested squares present in various parts of these fields. 
 The conditions of the examinations were made as uniform as was 
 possible. The fields were divided into blocks, and practically the 
 same ground was covered in each block upon succeeding examinations. 
 
 Table XXII. — Progress of infestation, field 1. 
 
 Block. 
 
 Date. 
 
 Number 
 
 of 
 squares 
 exam- 
 ined. 
 
 Number 
 
 of 
 squares 
 infested. 
 
 Percent- 
 age. 
 
 Remarks. 
 
 
 1903. 
 (June 8, 9 
 
 4,200 
 467 
 249 
 278 
 91 
 358 
 331 
 300 
 699 
 
 675 
 211 
 193 
 224 
 85 
 168 
 148 
 100 
 636 
 
 16.0 
 45.0 
 77.5 
 80.6 
 93.5 
 46.6 
 44.7 
 33.3 
 91.1 
 
 Work of hibernated weevils only. 
 Second generation at work. 
 Third generation beginning. 
 
 
 July 13 . 
 
 I 
 
 Uuly 22 
 
 
 August 4 
 
 
 
 About four generations now working. 
 Much cotton dying from root rot. 
 
 
 (July 30 
 
 II 
 
 1 August 1 
 
 
 1 August 4 
 
 
 
 [August 20 
 
 
 
 Total 
 
 
 
 6,973 
 
 2,440 
 
 35.0 
 
 
 
 
 
 The observations made in Block I cover a longer period, and are, 
 therefore, more suggestive than those made in Block II. Evidently 
 infestation began with the first appearance of squares. So long as 
 the hibernated weevils alone were at work the percentage did not 
 increase very rapidly, but with the advent of the second generation 
 
-7 
 
 a much larger proportion of the squares became infested. ( orre 
 Bponding increases are seen with the third generation, inn from that 
 time on so large a proportion <>f the squares was Infested thai the 
 percentage did not increase bo rapidly. It may be noted in each 
 block that the maximum percentage of infestation is slightly over 90. 
 Some clean squares ma\ always be found, however numerous the 
 weevils may be, bul those which escape weevil puncture are mostly 
 less than half gro¥ a, ><> thai while the percentage varies bu1 slight ly, 
 i(>u of these clean squares would escape the later attacks of the 
 weevils and form blooms. In Block I the infestation was quite gen- 
 eral. The situation of the block was especially favorable to the 
 hibernation of a Large number of weevils. Bounded on one side by a 
 fence row, on the opposite side by a cornfield, and at one end by I lie 
 buildings used by the tenant, an abundance of hibernating places was 
 
 afforded the weevils, and as a result they came into the field in the 
 spring from all those directions (PI. XIII, fig. 51). It was noticeable, 
 however, that the portion of greatest infestation early in the season 
 lay in the corner between the fence row and the buildings. From the 
 
 feme row especially the weevils spread toward the center of the field. 
 The second field, as has been slated, was comparatively isolated, so 
 that infestation first began late in the season. Block I in this case 
 lay in the corner between cross-roads. Block II adjoined the road 
 farther on, while the third block was taken as far from these two as 
 was possible. Infestation began in the corner covered by Block I. 
 In studying this block, lots 1, 2, and 3, as numbered in the table, were 
 taken diagonally across the block, away from the corner. Block II 
 was separated from Block I by corn, the ends of the rows being at 
 the road which passed the point of original infestation. The lots in 
 Block II were taken in their order at varying distances from the road. 
 Block III was some distance from the others. In this case lot 1 was 
 taken along the edge on the side toward the other blocks, while lot 2 
 was taken in the middle of the block. 
 
 Table XXIII. — Progress of infestation, field 2. 
 
 Block 
 
 Lot. 
 
 Date. 
 
 Number 
 
 of 
 squares 
 
 exam- 
 ined. 
 
 Number 
 
 of 
 squares 
 infested. 
 
 Percent- 
 age of 
 
 infesta- 
 tion. 
 
 Remarks. 
 
 
 
 1903. 
 
 fAUgUSt t) 
 
 885 
 414 
 210 
 800 
 362 
 L85 
 180 
 80S 
 138 
 150 
 800 
 818 
 859 
 166 
 330 
 
 15 
 351 
 
 18 
 
 
 841 
 
 i>2 
 156 
 
 31 
 105 
 
 9 
 130 
 
 20.0 
 
 
 
 1 
 
 2 1 
 
 [August 22 
 
 ^ \ j-Lot 2, iu middle of Block I. 
 
 I 
 
 August (> 
 
 
 : 
 
 2 
 
 3 
 
 1 
 
 [....do 
 
 0.0 (Lot 3, opposite corner of block 
 66 t> j from lot 1. 
 
 
 \ August 22 
 
 
 
 :<:{.:> (Lot 1, near public road, passing 
 86 7 I lot 1 of Block 1 
 
 
 
 IL 
 
 (August 13. 
 
 1 August 24 __ 
 
 15.3 
 
 77 2 
 
 
 [August 13. 
 
 6 
 
 
 [August 84.. 
 
 ('.:. n 
 
 
 [August 17 
 
 91 41.7 Edge of block. 
 888 88 
 
 n~L 
 
 | August 2M 
 
 August 17 
 
 :>s :.':' 9 Middle of block 
 
 
 [August 89 
 
 890 
 
 
 
 
 
 
 
88 
 
 From a study of Block I it is evident that infestation began some 
 time in July, since when first found it was entirely restricted to a 
 small area. A study of each block chronologically shows the steady 
 but rapid progress of the weevil, as does also a comparison of the 
 three blocks at the nearest possible dates. The tremendous activity 
 of weevils in midsummer and the possible rapidity of their spread is 
 clearly shown in this field. 
 
 A study of two other fields yielded practically similar results. The 
 dates of examinations, with the percentages found in each case, will 
 be given. In field 3 there was found, upon June 2, 3 per cent of infes- 
 tation; on July 16, 25.9 per cent; on August 15, 65.9 per cent. This 
 field was from native seed and was planted about three weeks earlier 
 than field 4, which was of King seed, and just across a turn row from 
 field 3. In field 4 infestation began very late, as on August 8 there 
 appeared to be only 2 per cent and on August 15, 23.6 per cent, while 
 on August 26 it had increased to 91.5 per cent, which is about the 
 usual percentage of maximum infestation. 
 
 Under the conditions usually prevailing cotton will cease to make 
 when about two-thirds of the squares have become infested, since the 
 weevils have then become sufficiently numerous to attack nearly all 
 of the remaining clean squares before they have time to bloom and 
 form bolls. Even bolls which have set before this percentage of 
 infestation is reached are not entirely safe, as the smallest ones will 
 be more readily attacked by weevils, as they have greater difficulty 
 in finding uninfested squares. 
 
 WEEVIL INJURY vs. SQUARE PRODUCTION. 
 
 At the beginning of infestation the indications of the weevil's pres- 
 ence are inconspicuous. Even wdien considerably advanced most 
 farmers do not recognize the injury, and thus are led to believe that 
 the insect has not appeared. Among the most conspicuous indica- 
 tions of the weevil's presence may be mentioned the falling of infested 
 squares. As the squares remain on the plant after they become 
 infested fully as long as they lie upon the ground between the time 
 of their falling and the emergence of the weevil, it is plain that less 
 than half of the actually infested squares will ordinarily be observed. 
 Previous to falling infested squares gradually turn yellow, and in 
 most cases flare somewhat; but flaring is by no means as closely related 
 to weevil injury as might be supposed. As the percentage of infesta- 
 tion increases the great numbers of squares on the ground must attract 
 attention (PL XII, fig. 46). Shedding of squares may take place for 
 other reasons than the attack of the weevil, but in fair weather, when 
 large numbers of squares are found upon the ground, the weevil is 
 probably present. As infestation approaches its climax there is a 
 great decrease in the number of blooms, and when a field is found at 
 blooming age with many squares, but no blooms, the weevils are 
 
 
B9 
 
 almost certainly abundant. The conditions named form the most 
 conspicuous indications of practically total infestation. Daring tin* 
 season of L903 ii was found thai a condition <>f total infestation was 
 reached some time between August I and 20 in most fields within the 
 infested area. This condition is, as a pule, coincident with the appear- 
 ance in large numbers of weevils of the fourth generation. The exact 
 time will varj in different seasons, and even in adjacent infested lie Ms, 
 because of \ arying condil ions. 
 
 No! only is the maximum number of weevils present in the field in 
 midsummer, but their capacity for injury is also greatest at that 
 time. Practically all of the crop that will be made must have been 
 set before this time. After this bolls will form only by accident. 
 
 A large scries of examinations made by Messrs. Harris and Morrill 
 at Calvert, Tex., shows the very rapid increase in the percentage of 
 infested squares which usually takes place a few weeks earlier than 
 it did in L903. 'The figures given in each column in the table show- 
 also the closeness with which the weevil activity kept pace with the 
 formation of squares after the period of maximum infestation had 
 once been reached. The general influence of climatic conditions may 
 be seen by a comparison of the last- two columns in t he table, but t his 
 point would be much more clearly shown by a series of examinations 
 made during the first half of the growing season, at which time tem- 
 perature and moisture would have greatest influence upon weevil 
 development and injury. One hundred squares were picked promis- 
 cuously in each block for the determination of the percentages given 
 in the columns for these 34 blocks, thus making a total of 17,000 
 squares examined. 
 
 Table XXIV. — Study of the infestation of cotton fields at Calvert, Tex. 
 
 Time of record. 
 
 
 
 
 Block. 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 1 
 
 8 
 
 9 
 
 Hi 
 
 11 
 
 IS 
 
 20 
 
 21 
 
 22 
 
 1903. 
 
 A u urn -t 15-17 
 
 72 
 
 '.if, 
 93 
 92 
 94 
 
 68 
 91 
 
 'Jl 
 si 
 93 
 
 64 
 96 
 
 92 
 89 
 
 91) 
 
 65 
 
 1(K) 
 91 
 91 
 90 
 
 71 
 96 
 9't 
 
 97 
 91 
 
 63 
 
 ;•; 
 
 94 
 98 
 98 
 
 66 
 98 
 93 
 
 91 
 88 
 
 v,s 
 98 
 92 
 89 
 83 
 
 59 
 
 90 
 95 
 89 
 92 
 
 60 
 87 
 98 
 
 91 
 
 99 
 
 59 
 90 
 
 94 
 94 
 
 96 
 
 60 
 88 
 96 
 96 
 
 94 
 
 4(i 
 98 
 88 
 95 
 
 95 
 
 4t> 
 95 
 89 
 94 
 93 
 
 55 
 
 September 2 i 
 
 S9 
 
 'HI 
 
 
 '11 
 
 ( October 22 :.'4 
 
 Ml 
 
 
 
 Time of record. 
 
 Block. 
 
 23 
 
 24 
 
 25 
 
 26 
 
 27 
 
 27 a 
 
 28 
 
 29 
 
 30 
 
 81 
 
 32 
 
 :$:5 
 
 50 
 
 51 
 
 52 
 
 Looa 
 
 August !•"> 17 
 
 4S 
 09 
 92 
 1)4 
 96 
 
 50 
 94 
 91 
 94 
 91 
 
 54 
 91 
 98 
 
 91) 
 89 
 
 47 
 91 
 94 
 96 
 
 98 
 
 49 
 B8 
 93 
 
 9:5 
 
 N 
 
 58 
 93 
 
 98 
 94 
 91 
 
 54 
 
 95 
 90 
 92 
 
 97 
 
 58 
 91 
 96 
 98 
 
 '.hi 
 
 :.i 
 91 
 94 
 95 
 
 54 
 93 
 
 96 
 99 
 95 
 
 57 
 93 
 93 
 94 
 97 
 
 55 
 W 
 
 91 
 
 96 
 93 
 
 62 
 
 89 
 9:5 
 92 
 96 
 
 66 
 
 94 
 
 92 
 
 87 
 97 
 
 58 
 
 September 2-4 . 
 
 % 
 
 September 14-17 
 
 95 
 
 October 1 :> 
 
 86 
 
 October 22-24 
 
 97 
 
 
 
90 
 
 Table XXIV. -Study of the infestation of cotton fields at Calvert, Tex.— Cont'd. 
 
 
 Block. 
 
 Average 
 
 infesta- 
 tion for 
 entire 34 
 blocks. 
 
 
 Time of record. 
 
 :»:! 
 
 54 55 
 
 ;.<> 
 
 Climatic conditions. 
 
 August 15-17 
 
 September 2-4 
 
 September U-17.. . 
 
 October 1-3,. 
 
 October 22-24 
 
 (14 
 
 89 
 91 
 78 
 95 
 
 69 
 
 94 
 
 96 
 92 
 99 
 
 67 
 
 90 
 97 
 
 88 
 
 98 
 
 62 
 
 97 
 95 
 89 
 95 
 
 /'<<<;, it. 
 
 58.88 
 
 91.41 
 
 93.21) 
 
 <u..v, 
 
 93.67 
 
 Rainfall in July. 1903. 8.61 inches (or nearly 
 
 four times normal rainfall »: Aug. 1 to 15, 
 
 nearly normal rainfall (0.79inch, Aug. 2). 
 
 Average temperature, July, 85° F.; Aug. 
 
 1 to 15. 85J° F. 
 
 Rainfall from Aug. 15 to Sept. 2, 0.9 inch 
 (nearly normal). Average temperature, 
 same period. 84i° F. 
 
 Rainfall from Sept. 2 to 14, 0.8 inch (about 
 one-half normal; . Average temperature. 
 83*° F. 
 
 Rainfall from Sept. 14 to Oct. 1. 0.14 inch 
 (about one-tenth normal) . Average tem- 
 perature, 76?° F. 
 
 Rainfall from Oct. 1 to 22. 3.63 inches (more 
 than two times normal). Average tem- 
 perature, 74° F. 
 
 Still another series of observations made by Doctor Morrill, at Austin, 
 Tex., shows that similar conditions prevailed in localities nearly 100 
 miles apart. For each of these percentages 300 squares were exam- 
 ined, thus making 14,400 observations in the series. 
 
 Table XXV. — Study of the infestation of cotton fields at Austin, Tex. 
 
 Time of record. 
 
 Block. 
 
 1 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 1903. 
 August 4-7 
 
 29.0 34.0 
 95. 3 95.0 
 90. 3 88.0 
 
 11.0 
 95.3 
 90.3 
 
 15.0 
 96.7 
 90.0 
 
 10.0 
 92.7 
 94.7 
 
 9.0 
 87.3 
 a5.3 
 
 19.0 
 95.0 
 92.0 
 
 33.0 
 
 !'ti. 7 
 92. 
 
 43.0 
 96.7 
 96.0 
 
 43. 
 96.7 
 96.0 
 
 36.0 
 95.3 
 92.7 
 
 31.0 
 
 September 7-9 
 
 October 5-7 
 
 93.7 
 96.0 
 
 
 Block. 
 
 Average 
 infesta- 
 tion, en- 
 tire 16 
 blocks. 
 
 
 Time of record. 
 
 13 
 
 14 
 
 15 
 
 16 
 
 Climatic conditions. 
 
 1903. 
 August 4-7 
 
 33.0 
 93.7 
 92.0 
 
 36.0 
 98.0 
 89.3 
 
 49.0 
 98.3 
 92.7 
 
 55.0 
 97.7 
 92.7 
 
 Per cent. 
 30.37 
 
 95.25 
 
 91.87 
 
 Julv rainfall, 12.65 inches (above nor- 
 
 September 7-9 
 
 October 5-7 
 
 mal 10 35 inches). Mean average 
 temperature. July. 82.6° F. 
 
 August rainfall. 0.79 inch (below 
 normal 1.64 inch). Mean average 
 temperature. 82.6° F. 
 
 September rainfall, trace i below nor- 
 mal 3.72 inches i. Mean average 
 temperature. 76° F. 
 
 As the first records at Austin were made about ten days earlier 
 than were those at Calvert, the}' serve to show a much greater total 
 increase in the average infestation during August, though the average 
 daily increase in the percentage of infestation agrees very closely in 
 the two localities, being 1.8 per cent at Calvert and 1.9 per cent at 
 Austin. 
 
 A decrease in square production accompanies the maturity of the 
 bulk of the crop, owing to the fact that the assimilative power of the 
 
91 
 
 plant is largely consumed in maturing seed. Dry weather normally 
 occurring at thi> period also causes a decrease in the number of 
 weevils present. Not only are there Less squares to become infested, 
 inn each square is also subjected to greater injur} . and many which 
 would otherwise have produced weevils are unfitted as food for the 
 larvae by the decay which follows the numerous punctures. Several 
 eggs may be deposited in one square, bu1 as a rule only one weevil 
 will result. At this season weevils turn their attention to young bolls 
 upon which the injury previous to ihis time has been comparatively 
 slight. It was found in one ease iliat •'!•'» or l<> percent of the bolls 
 were infested, while l ."> percent of the squares were yet clean. The 
 Longer period of development required by larva* in bolls also serves to 
 decrease the number of weevils produced. While the actual number 
 of weevils begins 1<> decrease within a short time after the period of 
 maximum infestation is reached, the apparent numbers may possibly 
 be greater. The decreased number of squares serves to concentrate 
 the weevils upon those remaining, and therefore the number of weevils 
 found in any square will be so much the greater. 
 
 RELATION OF WEEVILS TO "TOP CROP." 
 
 The hope of gathering a top crop is the " will-o'-thc-wisp" of cotton 
 planters. After considerable cotton lias been matured fall rains often 
 stimulate the production of a large number of squares, and many 
 planters arc misled by the hope of gathering a large top crop from 
 this growth. The joints of the plant are short, and the squares are 
 formed rapidly and near together. Though weevils may have been 
 exceedingly numerous in the field, their numbers will have become so 
 decreased in the manner described under the preceding heading that 
 they can rarely keep up with the production of squares at this period 
 of rapid growth. Many blooms may appear, and the hope of a large 
 top crop increases. 
 
 The fact, however, as stated by prominent growers, is that before 
 the appearance of the weevil they actually gathered only about three 
 top crops in 25 years. The chance of its development, though always 
 small, becomes hopeless wherever the weevil is present in consider- 
 able numbers. (See Tables XXIII, XXIV, and XXV, and average of 
 infestation of entire fields, p. 8S.) Neither the hopelessness of gath- 
 ering a top crop nor the actual injury which is being done to the crop 
 of the succeeding year by allowing that growth to continue until 
 frost kills it is generally appreciated by planters. Because of the 
 apparent abundance of squares and the presence of many blooms the 
 plants are allowed to stand long after they might otherwise have been 
 destroyed. As is the case in the early spring, however, the abun- 
 dance of squares increases greatly the production of weevils; and 
 though a few bolls may set. they are almost certain to become infested 
 before they reach maturity. Every condition, therefore, contributes 
 
92 
 
 to the production of an immense number of weevils very late in the 
 season and at just the right lime for their successful hibernation. 
 As the result of this, far greater injury is done to the crop of the 
 following season, with a comparatively small gain in the yield of the 
 present season. Furthermore, plants standing until frosts kill them 
 are often allowed to stand throughout the remainder of the winter, 
 and these furnish an abundance of favorable hibernating places for 
 the weevils. The consequence of this practice is that so many weevils 
 are carried through the winter alive that the yield of the next year 
 will be much less than what it might have been but for the farmer's 
 indulgence of the forlorn hope of a top crop. 
 
 From these considerations it seems plain that within the weevil ter- 
 ritory all hope of a top crop must be given up and the destruction of 
 the stalks be practiced as early in the fall as may be possible. This 
 practice is one of the essential elements in the successful control of 
 the weevil. 
 
 SOME REASONS FOR EARLY DESTRUCTION OF STALKS. 
 
 It is naturally impossible to fix any date for the destruction of stalks 
 which would apply to all localities and under all conditions. The 
 condition of the soil must be considered as well as that of the maturity 
 of the crop. While the condition of the soil can not be changed, the 
 time of the maturity of the crop is largely within the control of the 
 planter, since by early planting of early maturing varieties nearly 
 the entire yield may be matured before the usual time of picking of 
 the first cotton from native seed. Whatever the qualifications which 
 must be made, the}^ do not decrease the general strength of the reasons 
 which may be given for the early destruction of stalks. The principal 
 reasons are three in number: 
 
 First, the absolute prevention of development of a multitude of 
 weevils which would become adult within a few weeks of hibernation 
 time. The destruction of the immature stages of weevils already 
 present in infested squares is surely accomplished, while the further 
 growth of squares which may become later infested is also prevented. 
 This stops immediately the development of weevils which would nor- 
 maUy hibernate successfully, and by decreasing the number of wee- 
 vils which will emerge in the spring the chances of a good crop for 
 the following season are greatly increased. 
 
 The second reason is that by a proper manipulation of the stalks 
 a very great majority of the weevils which are already adult can be 
 destroyed. One of the most successful practices is to throw the stalks 
 in windrows, and as soon as they have become sufficient^ dry they 
 may be burned. If the weather is favorable, the burning may take 
 place in about two weeks, and many of the weevils will not have left 
 the cotton stalks by that time. In case rains delay the drying it will 
 be found advantageous to expedite burning by the use of crude petro- 
 

 98 
 
 learn. Grazing the fields with cattle, as some have recommended, 
 will destroy much of the growth and prevent further development of 
 weevils, but M allows enough <>f foliage i<> remain to Bustain th<' life 
 of many which are already adult until it becomes sufficiently cold for 
 them to hibernate. Not only does burning destroy most of the wee- 
 vils, but it also destroys the shelter which might be afforded the few 
 thai would escape, and the chances of successful hibernation are 
 largely decreased by this practice. 
 
 The third reason may be found In the fact that the clearing of the 
 ground renders possible a deep fall plowing. This catches such wee- 
 vils as might still be in squares on the ground. The ground becomes 
 clean by this practice, so that no vestige of the food plant remains, 
 
 and living weevils, if by any possibility they have escaped thus far, 
 must either starve or. perish from exposure. Furthermore, fall plow- 
 big places the ground in the best possible condition and makes it 
 ready for immediate working as early as planting may begin in the 
 spring, thereby saving delay in the starting of the crop. As stalks 
 must be destroyed in some way before the field can be replanted, the 
 practices here mentioned will not add greatly to the cost of dest ruc- 
 tion. Even if some cotton is present upon the stalks at the time of 
 their destruction, this small item is hardly worthy of consideration in 
 comparison with the greatly increased crop and the more early matur- 
 ing and better quality of staple which may be obtained by the adop- 
 tion of this recommendation. 
 
 Having studied carefully the methods of weevil control which 
 have heretofore been recommended, the writers firmly believe that 
 the destruction of the stalks in the early fall is the most effective method 
 known of actually reducing the numbers of the weevil. Early destruc- 
 tion will cost but a small fraction of the expense necessary to the fre- 
 quent picking up of the squares infested by hibernated weevils in the 
 spring, and is far more thorough as a means of reducing the numbers 
 of the weevil than is the practice of picking hibernated weevils from 
 the young plants. 
 
 Early dest ruction of the stalks is essential to the greatest success of 
 any system of controlling this pest. All other practices recom- 
 mended — early planting of early maturing varieties, thorough culti- 
 vation, fertilization, etc. (see p. 112) — though very valuable in securing 
 the crop, are perhaps of greatest value because they prepare the way 
 for this early destruction which so reduces the actual number of wee- 
 vils hibernating successfully that the other recommendations may 
 yield their best results. Since t he earliest investigations made by this 
 Division upon the boll weevil, it has been recognized that this prac- 
 tice is of the first importance, and the experience of recent years has 
 but added certainty to this conviction. Planters have, however, been 
 slow to change their methods of cultivation, but enough have adopted 
 the recommendation to prove its efficiency. It must not be thought 
 
94 
 
 that the procuring of the immediate crop is the only desideratum. 
 Early and complete destruction of stalks is undoubtedly the most 
 important single element insuring success for the subsequent year. 
 
 DISSEMINATION. 
 
 Two principal periods of dissemination may be found during a sea- 
 son. The first is when the hibernated weevils leave their winter 
 quarters and go in search of food. Having found food, the spread is 
 mainly controlled by the limitation of the food supply. So long as 
 an abundance of growing tips or of clean squares is near at hand 
 weevils will not travel far, but when the condition of total infestation 
 is reached the period of greatest dissemination is also attained. 
 
 In any given field dissemination takes place mainly by the short 
 flights and crawling of the weevils. The search of the female for unin- 
 fested squares is the principal factor in their movement. Heavy 
 winds seem to be of comparatively small importance, as weevils do 
 not take flight readily at such times; but light, warm breezes, such as 
 prevail throughout the coast country of Texas, undoubtedly tend to 
 carry them in a general northerly direction, and the continuous equi- 
 noctial storms of the fall in Texas, occurring at the very time the 
 pests are most active, have undoubtedly had a strong effect in the 
 same direction. 
 
 The two principal lines of spread will be found along railways and 
 water courses. Between localities separated by short distances, traffic 
 along highways is probably the chief factor. The distance which a 
 weevil may travel in flight has never been determined, but from a 
 study of their habits of flight it would seem to be comparatively short. 
 Floods and the motion of water along water courses frequently serve 
 to distribute many weevils along the edge of high- water mark. As 
 river valleys are largely devoted to cotton culture, this would seem to 
 be no small factor in the transportation of the weevils. 
 
 Over longer distances the usual means of commercial traffic must 
 be held responsible. Shipments of cotton, whether for ginning or in 
 baled condition, are likely to carry many weevils. Shipments of seed 
 for planting, coming from infested localities, are almost certain to 
 carry weevils, and shipments of seed to oil mills may also assist in 
 scattering them. The pests are often carried far outside of infested 
 regions in the shipment of seed to northern oil mills. From the mills 
 they are carried to the farms in the hulls or other by-products used 
 for feeding cattle. Many of the isolated colonies in northern Texas 
 originated in this manner. 
 
 WEEVILS IN SEED HOUSES AT GINNERIES. 
 
 Careful observations made by Mr. Schwarz at Victoria throughout 
 the winter of 1901-2 revealed great numbers of weevils about the gins. 
 They occurred especially in the seed houses, and the danger of the 
 
transportation <>f the pests from one Locality i<» another was most 
 evident . 
 
 A. casual examination of the dirt separators which are qo^ Id use 
 in the more modern ginneries shows that immense numbers of wreevils 
 brought in from the fields are separated from the Lint by these devices. 
 Even where these separators are used, however, a short search in tin- 
 seed house will shom that many weevils pass through alive. A single 
 hour's search in the Bced house of a first-class ginnery, where dirt 
 separators are in use, yielded seven boll weevils in perfect condition, 
 and a number of other and much Larger insects. In addition t<> these 
 a number of fairly Large spiders, most of which were in perfect condi- 
 tion, were also found. Numerous pupa' may pass through the gins 
 unharmed in the cells formed by the larva*. These cells are similar, 
 both in size and shape, to the seed, and may often be mistaken Ihere- 
 for (PI. XI., fig. 44). Distribution of weevils in seed is therefore 
 easily possible, and nninfested localities should guard carefully 
 against importing weevils in this way. 
 
 The most valuable suggestion for reducing the important effect 
 that gins have in spreading the weevil is in the improvement of the 
 cleaning devices referred to above, and in encouraging -their more 
 general use. A particular study of this matter will be made during 
 tin- season of 1U04. 
 
 NATURAL CONTROL. 
 
 Doubtless many factors are concerned in the natural control of the 
 boll weevil. The most important ones are probably included among 
 the following topics: 
 
 MECHANICAL CONTROL. 
 
 PILOSE OBSTACLES TO WEEVIL PROGRESS. 
 
 In testing the susceptibility of various cottons to weevil injury it 
 was found that the variety of Egyptian cotton grown (Mit Afifi) was 
 more severely injured than was any other. The next in order were 
 Sea Island and Cuban tree cotton, while the American cottons, repre- 
 sented especially by King's Improved, were less severely injured than 
 were any of the others. It may be noted that the three varieties first 
 mentioned seem more closely related to each other than any of them 
 do to the American. The reason for the evident choice of these cot- 
 tmis was carefully sought for, but the only difference which seemed 
 worthy of consideration was found in the varying degree of pilosity 
 upon the stems (PI. XIII, fig. 50). It was found that Egyptian stems 
 were almost perfectly smooth, while Sea Island and Cuban resembled 
 it closely in that respect. Many American cottons, and King's 
 Improved especially, are quite pilose, and it was often noted that upon 
 these weevils showed some slight difficulty in moving about or in 
 climbing the pilose stems of the plant. While this obstacle to weevil 
 
96 
 
 activity may seem slight to account for the evident selection of the 
 smoother varieties, no greater difference could be found. As is shown 
 by Table XI, on page 46, the selection is not due to a difference in tasti 
 of i in' squares. 
 
 Tn order to test the resistance which varying degrees of pilosity 
 might offer to weevil progress, a number of experiments were mad' 1 
 with various stems or fruits. In climbing upon the stems of Kin- 
 plants weevils would catch the spines with the forefeet while pushing 
 themselves upward by means of the tibial spurs of the hind Legs 
 placed against the epidermis and between the spines. It was evidem 
 that their progress was considerably hindered, and several attempts 
 were often made before a firm foothold was secured. 
 
 Okra pods were next tried, as upon them the spines are very short 
 and stiff. Weevils climbed these pods with little difficulty. 
 
 The seed pods of Sunset Hibiscus were also tested. The spines 
 upon these are from 2 to 3 millimeters long; they stand thickly and 
 are quite stiff. Over these spines weevils walked easily, but though 
 they attempted vigorously to get their heads down between the spines 
 far enough to feed, they were unable to do so. A number of weevils 
 were kept -for several daj T s upon these pods, but they were unable to 
 feed. The spines were then removed from a small area, and the 
 insects began to feed immediately. 
 
 Weevils travel with difficulty over loose cotton fibers, as their feet 
 become entangled among them. 
 
 DESTRUCTION OF LARVJB AND PUP.E IN BOLLS AND SQUARES BY 
 ABNORMAL PLANT GROWTH. 
 
 In making examination of several thousands of infested squares a 
 small percentage was found in which the larvae had evidently been 
 killed by an abnormal condition of the interior, which may be char- 
 acterized as a process of gelatinization. This change begins at the 
 point of injury and spreads. Instead of the normal growth of the 
 anthers there takes place a change which appears to be something like 
 the swelling of starch granules. The interior becomes soft and pulpy, 
 and by the swelling considerable internal pressure is prod need. The 
 death of the larva? results either from unfavorable food conditions or 
 from the internal pressure, which in many cases is sufficient to distort 
 the square. Whether from these or other causes, from 10 to 20 per 
 cent of the larvae usually die within the squares. 
 
 Gelatinization sometimes occurs in small bolls, but more rarely as 
 bolls become larger and more mature. In large bolls in which seeds 
 are nearly matured the feeding of the weevil larvae often causes seeds 
 to sprout, and in several such cases pupa? have been found crushed 
 by the rapid growth of the caiilicle. 
 
 In examining nearly 1,000 bolls, taken partly from King and partly 
 from native cotton, it was found that in the early maturing King the 
 

 Pla- • 
 
 \IS> 
 
 59 
 
 61 
 
 ^-r^ 
 
 SF' 
 
 /^, 
 
 
 
 w 
 
 Insects Often Mistaken for the Boll Weevil. 
 
 Figs. 59, 60, Transverse Bans i Barfs ti<insr,r.<<i i. much enlarged (original i; fig. 61, Oentrinus peni- 
 eellw, enlarged (original i: riir. 62, coffee-bean weevil i Araect rus fasdculotus): a, larva: b, beetle; 
 • ■. pupa, enlarged (from Chittenden); figs. 63, 64, Chalcodermus smeus, enlarged from Chitten- 
 den i. 
 
Bui. 4". 
 
 XVI. 
 
 1 ; -¥f 
 
 Insects Often Mistaken for the Boll Weevil. 
 
 Figs. 65, 66, Sharpshooter [HomaZodisea triquetra), enlarged from Insect Life); fig. 67, cotton 
 stainei (Dysdereus suturellus), enlarged (from [nsecl Life); fig. 68, cotton stalk borer [Ataxia 
 crypto), enlarged (from Howard); tig. 69, imbricated snout beetle [Epicaerus iwJbricaius), 
 enlarged (from Chittenden); fig. 70. snapping beetle [Monocrepidius vespertinus), enlarged 
 (from Chittenden i. 
 
97 
 
 rcontage of larvw and pupn killed was much Larger than In the 
 In native cotton about 20 per <-<"nt <>f the larvas wrere found 
 to be dead, w l> i l<- In the King U.2 per cent were dead. In all proba- 
 bility the more rapid M<>\n of Bap in the early developing King cotton 
 largel) responsible for the changes which led to the death of the 
 
 CLIMATIC CONTROL. 
 
 [iNFLl ENCE OF * LDfATIG CONDITIONS UPON WEEVIL MULTIPLICATION 
 
 \\D i\.iii;v. 
 
 Three principal factors affect the development, spread, and dest ruc- 
 tivenesa of the boll weevil— temperature, precipitation, and food sup- 
 ply. So perfectly has the weevil become adapted to Its single food 
 plant that it is a very not Iceable tact thai the climatic condil ions which 
 are most favorable to the growth of the plant are most favorable also 
 for the normal activities and development of the weevil. Affecting 
 one in the same direct ion as the other, the pest is, therefore, enabled to 
 very closely keep pace with its food supply under all kinds of natural 
 condil ions! 
 
 The most favorable conditions for the weevil area high tempera- 
 ture and abundant moisture throughout along season. These con- 
 ditions favor the growth of the plant and produce a very large 
 number of squares, which supply abundant opportunity for the rapid 
 multiplication of the weevils. Severe drought checks together the 
 growth of the plant and the development of the weevils. It has not 
 yet been determined whether the death of larvae in fallen squares 
 exposed directly to the rays of the sun is due principally to the heat 
 produced or to the complete drying of the food supply. It is certain, 
 however, that one or both of these factors produce a large mortality 
 among the larva* and pupae so exposed during long-continued hot and 
 dry weather occurring before the plants have become large enough 
 to shade most of the ground. After that the shade produced pre- 
 vents most of the good work of the sun in destroying weevils. 
 
 It is often said by cotton growers that "rain brings the weevils." 
 The principal reasons for this idea are that rains, in squaring time 
 especially, produce conditions greatly favoring the immediate devel- 
 opment and subsequent injury of weevils, while at the same time 
 they make more apparent the amount of injury already done. An 
 abundance of rain following a long dry period naturally causes greal 
 numbers of squares to fall from purely physiological causes, while at 
 the same time it knocks to the ground such previously infested 
 squares as have become weakened in their connection with the plant 
 and which would fall naturally within a tew days. The Large number 
 of squares to be found on the ground immediately after a storm would 
 seem to account for the prevalence of the opinion mentioned. A 
 large degree of moisture in fallen squares seems to favor directly the 
 2 1 7:59— No. 45—04 7 
 
98 
 
 growth of larvae within, thus producing quickly a large number of 
 weevils ready to do further injury. 
 
 It is still an open question as to how low winter temperatures the 
 weevil can withstand. It is certain that in southern Texas many 
 Larvae and pupae slowly continue their development during the winter 
 season. Mr. S. G. Borden, of Sharpsburg, Tex., in a letter written 
 January 27, 1896, says: "Hands clearing up cotton stalks report 
 plenty of the larvae in dry bolls." Mr. Schwarz found weevils hiber- 
 nating in ail stages, except the egg, at Victoria, Tex., during Febru- 
 ary, 1902. At the same locality in January and February of 1904, the 
 weevils in larval, pupal, and adult stages were taken alive from dry 
 bolls by Mr. J. D. Mitchell, a resident and cotton planter of that place. 
 
 After the weevils first made their appearance at San Antonio in the 
 fall of 1895 they were supposed to have been entirely destroyed by 
 frosts during the following winter. The lowest temperature recorded 
 at San Antonio for that winter was 26° F. on December 30, 1895. 
 On January 2, 1896, Professor Townsend made an examination of the 
 condition of the weevil, and, so far as he found, all larvae in bolls were 
 then dead, while pupae and adults were all alive. In spite of the mild- 
 ness of the remainder of the winter the weevils did no damage to the 
 crop of 1896, and were not found in fields in which they were present 
 the year before. In writing of this unexpected condition, on October 
 19, 1896, Professor Townsend says, "The timely drought of last of 
 May and first of June is what killed the weevils this year." There is 
 therefore some doubt as to whether frosts or drought were responsible 
 for the destruction of the weevils at San Antonio in 1896. 
 
 At Victoria, on February 17, 1903, the lowest temperature recorded 
 by the Weather Bureau report was 20° F., but many weevils hiber- 
 nated successfull\\ Doubtless much lower temperatures than this 
 were experienced in more northern localities in the weevil belt, but 
 in no place have the weevils been exterminated thereby. 
 
 EFFECT OF RAINS UPON DEVELOPMENT OF WEEVILS. 
 
 AVliile it is a mistaken idea that rains first bring the weevils, it is 
 true that they favor weevil increase in several ways. Frequent rains 
 increase the growth of the plant and lead to the production of a larger 
 number of squares which may become infested. Driving rains knock 
 off infested squares, and by softening and moistening the food hasten 
 the development of the larvae within. Squares which are already 
 upon the ground are protected during rainy weather from sunshine 
 and drying. Rain hinders the enemies of the weevil far more than it 
 does the development of the weevils themselves. In several such 
 ways rains contribute directly or indirectly to the more rapid multi- 
 plication of weevils and cause the common impression among cotton 
 planters alluded to above. 
 
99 
 
 inn i OF w EST WTNTKB w i:\tii 1,1; ON n l BERN \ ti \< I wi.i\m 
 
 Owing bo the writers' absence from Victoria during the winter 
 months, observations could not be made directly or immediately upon 
 
 this point. It was found, however, that all weevils iii hibernation 
 tests which passed the winter successfully had been kept dry. The 
 winter of 1902- 3 was unusually wet at, Victoria, and the number of 
 hibernated weevils which were to be found on early cotton plants was 
 noticeably less than during previous seasons which had been dry. It 
 semis probable, therefore, that as many weevils perish from frequent 
 wetting as from exposure to the cold. 
 
 EFFECTS OF OVERFLOWS IN FIELDS. 
 I ' nusuallv favorable conditions for these observations were obtained 
 
 at Victoria in the season of L903. During the latter part of February 
 an overflow of the Guadalupe River covered many of the cotton fields 
 along its course. The fields in which especial study was made were 
 
 wholly submerged from one to several days. Cotton was planted in 
 some of these fields between March 15 and 17. Owing to cold 
 weather the growth of the plants was delayed and squaring did not 
 begin until between May 10 and 17. Immediately after this date it 
 was found that weevils were present and at work, and fallen squares 
 were first found about May 23. From a study of this field it became 
 apparent that the overflow had caused a considerably less decrease 
 than had been anticipated in the number of hibernating weevils. 
 Possibly the fact that the winter of 1002-3 had been exceptionally 
 rainy may account for the lack of contrast in weevil abundance in 
 overflowed fields and those which did not suffer in this way since, as 
 has already been noted, hibernated weevils were unusually scarce, 
 even on uplands. 
 
 Another period of high water occurred during the last of .June and 
 the first of July and gave a convenient opportunity to note its effect 
 ui^on active weevils. Many fields were partially and some wholly 
 submerged. This condition lasted for several days. Examination 
 made after the recession of the water showed that many fallen 
 squares which had certainly been in the water for some time con- 
 tained uninjured larva' and pupae. Naturally eggs and larva' 
 found in squares upon the plants, even though under water for some 
 time, escaped unharmed. Weevils were working normally upon the 
 plants. No diminution in their numbers could be seen and it was 
 apparent that the overflow caused no check either to the develop- 
 ment of the immature stages or to the activity of the adults. These 
 observations emphasize the fact that the weevil can not be drowned 
 out. 
 
100 
 
 LAI, ORATORY OBSERVATIONS UPON TIME WEEVILS WILL FLOAT OR 
 ENDURE SUBMERGENCE. 
 
 These tests were divided into two parts, each of which includes 
 botli the immature and mature stages. In each part floating and 
 submergence were tested. 
 
 Sixty squares, believed from external examination to be infested, 
 were floated in a driving rain for six hours. They were then removed 
 and left for several days, during which time 75 per cent of them pro- 
 duced normal adults. Ten squares which were floated in driving rain 
 for six hours were opened at once, and in every case found to be but 
 slightly wet upon the inside. These contained 6 larvae and 4 pupae, 
 and all were in perfect condition. 
 
 As squares float normally, submergence tests were considered 
 extreme. Five squares were submerged for six hours, and after that 
 produced 3 normal adults; 1 pupa died, and 1 square was found to 
 have been uninfested. Five more squares were submerged for thirty- 
 one hours. These produced 2 normal adults, and 1 pupa died in the 
 process of molting after removal from the square. Death was prob- 
 ably caused in the last case by drying; 1 square was found to contain 
 a dead pupa, and 1 was not infested. To test the possibility of its 
 living, should the square be penetrated by water, a naked pupa was 
 submerged for six hours, but in spite of this unusual treatment it 
 produced a normal adult. 
 
 In the tests made upon the floating power of adults, weevils were 
 isolated and placed in water in tumblers. They were dropped from a 
 considerable distance above the surface, so that they became entirely 
 submerged, and then floated to the surface naturally. The surface 
 tension of the water was found to be sufficient to float weevils which 
 were placed upon it carefully. The generally hairy condition of the 
 surface of the weevil's body prevents its being readily wetted, so that 
 it may struggle for some time in the water without becoming really 
 wet. When dropped in this way weevils float head downward, with 
 the tip of the abdomen above the surface. In the submergence tests 
 weevils were held down by a wire screen, and all bubbles were 
 removed from their bodies by a pipette, thus making the tests as 
 severe as possible. 
 
10 
 
 T \i'i i X X \ I /.'//' ctn of floating <ni<i aubnu r</> nee on all .-/«»./. 
 
 ConditloiiH ..[ tenl 
 
 Sim \ squares floated In 
 
 ram 
 
 Ton squares floated In rain 
 
 Five squares submerged 
 
 1).. 
 
 ( hoe naked pupa submerged 
 Ten adults floated 
 Do.. 
 
 Pive adults submerged 
 
 Do 
 
 I),-,, I Tmi " 
 Tims ,V': , before 
 
 "' ,,M nation 
 
 Nor 
 
 mill 
 
 adults 
 best. 
 
 Ten adults submerged 
 
 Four teen adults submerged 
 
 Hours. 
 
 i; 
 
 
 i to - 
 
 t; 
 
 Nona 
 
 None 
 
 SI 
 
 1 pupa 
 
 5 to 8 
 None 
 
 e 
 
 86 
 112 
 
 II 
 ll 
 
 1 
 
 
 16 
 
 
 
 
 86 
 48 
 
 9 
 
 u 
 
 
 KouutrkH. 
 
 ."• squares contained dead larva*: 
 :{ pupsa destroyed by ants, and '. 
 uninfested 
 
 Squares bnl slightly w.-t Inside B 
 
 larva- and ."> pupSB all alive and 
 
 QormaL 
 I pupa dead: l square uninfested 
 
 I pupa and :.' larva- alive aft 
 
 squares not we\ much inside. 
 
 ■" feed, but i died 
 in from :'. to 7 days; l lived 86 days 
 
 and laid 58 ■ 
 
 :i males died soon; females laid 48 
 
 eggs in ir> weevil-days. 
 1 lived through test, but never fed. 
 
 Iii the case of squares floating normally it is evident that they 
 might remain in water for several days without injury to the weevil 
 within. Very slight wetting of the cell takes place even under the 
 ext i-enie conditions of submergence. The effect of a brief flood would 
 in ii, therefore, be at all injurious. As adults float as readily as do 
 squares, they may also be carried long distances, and, furthermore, they 
 arc able to crawl out of the water onto any bushes, weeds, or rubbish 
 which they may touch. Even when floating for several days continu- 
 ously they are able to live and may be carried directly to new fields. 
 The floating of adults and infested squares explains the appearance 
 of weevils in great numbers along high-water line immediately after 
 a flood, and indicates that probably the most rapid advance the pest 
 will make in the United States will be into the fertile cotton lands of 
 the Red River Vallej' in Louisiana. 
 
 PROBABILITIES AS TO THE INFLUENCE OF CLIMATE OX THE WEEVIL 
 IX COTTON REGIONS XOT NOW IXFESTED. 
 
 The influence which the lower temperature prevailing over the 
 northern edge of the cotton belt may have upon the development, 
 desl iin-tiveness, and spread of the weevil is as yet largely problemat- 
 ical. No considerable amount of accurate data upon the development 
 of the weevil being at present available except that collected al Vic- 
 toria, Tex., during the seasons of 1902 and 1903, it is impossible to 
 predict with certainty how far or how rapidly the weevil may spread 
 or the rapidity of development which may take place under the differ- 
 ent climatic conditions prevailing in regions not at present infested, 
 or whether it may be expected that its destructiveness to cotton will 
 be materially reduced in other sections. These questions are, how- 
 ever, of considerable interesl because of the probability that the 
 
102 
 
 weevil will ultimately spread over the entire cotton belt in spite of 
 any measures which may be adopted to retard its progress. 
 
 During the past centuiy the attention of many botanists and zool- 
 ogists has been drawn to the relations existing between geographic 
 areas and the distribution of plants and animals. In this country 
 the limits of the well-defined zones and the laws governing the distrib- 
 ution of plant and animal life through those zones have been most 
 carefully determined by Dr. C. Hart Merriam, Chief of the Division of 
 Biological Survey of the United States Department of Agriculture. 
 A few years before the publication of Doctor Merriam's completed 
 results Dr. L. O. Howard, Chief of the Division of Entomolog}^ first 
 applied the principles underlying geographic distribution to a study 
 of the probable spread of a number of species of very injurious 
 insects, most of which had been imported into this country, 6 and 
 recently he has made a more extensive study of a very practical 
 nature concerning the geographic distribution of the yellow fever 
 mosquito/ Many observations have shown that in general the limits 
 of the spread of an imported insect pest may thus be approximately 
 determined. It is, therefore, not out of place to consider at this time 
 some points in regard to the probable status of the boll weevil in the 
 cotton belt outside of Texas. 
 
 According to the map published by Doctor Merriam, the entire 
 cotton-growing area of the United States lies within the Lower Austral 
 Zone, the northern limit of which is marked by the isothermal line 
 showing a sum of normal positive temperatures (above 32° F.) amount- 
 ing to 18,000° F. The weevil has alread} 7 become established near Sher- 
 man, Tex. As nearly as can be told from data at present available, the 
 isothermal line passing through Sherman, if extended eastward, would 
 pass along the Red River Valley, through the extreme southern part 
 of Arkansas, across central Mississippi and Alabama, a little south of 
 Atlanta, Ga., and thence curve northeastward through South and 
 North Carolina. It therefore becomes evident that "temperature" 
 will not prevent the spread of the weevil eastward. Even if it should 
 not go beyond the isothermal line within which it now thrives, its 
 territory would still include most of the great cotton belt of the United 
 States. Furthermore, there is no evidence to show that the weevil has 
 yet reached its most northern limit, and the probabilty remains that it 
 may yet show itself capable of existing anywhere within the Lower 
 Austral Zone where cotton can be grown. 
 
 A comparison of the positive temperatures of various localities in the 
 
 « Bulletin 10, U. S. Dept. Agr., Division of Biological Survey, Life Zones and 
 Crop Zones of the United States. 
 
 &Proc. Entorn. Soc. Washington, Vol. Ill, No. 4, pp. 219-226. "Notes on the 
 Geographic Distribution in the United States of Certain Insects Injurious to Cul- 
 tivated Crops."' 
 
 c Treasury Department— Public Health Reports, Vol. XVIII, No. 46. 'Con- 
 cerning the Geographic- Distribution of the Yellow Fever Mosquito." 
 
in:; 
 
 northeastern pari of iii«' cotton belt with thai of Victoria, Tex., dur 
 tag the si\ months from June I i<> November 30, L902, naturally 
 reveals a considerable range of difference, as does also r comparison 
 of lie average temperatures prevailing in those localities during the 
 same period for tin* preceding eleven years. Wherever ii Is con 
 Bidered In its effect upon the development of the weevil the tempera- 
 ture given is expressed in degrees of effective temperature — that is, 
 the actual temperature above 43 F. The mean average effective 
 temperature for any month multiplied by the number of days included 
 has been considered as giving the total effect ive temperature for that 
 month. While this method docs not give exactly the correct figures, 
 ii will furnish data for a comparison of the various Localil Les, and this 
 study of temperatures will undoubtedly reveal facts which will exert 
 considerable influence upon the status of the weevil in other loealii ies 
 into which it is liable to spread. 
 
 The total effective temperature for Victoria, Tex., from June 1 to 
 November 30, 1902, was 6,607° F. For the same period at Dallas Tex., 
 it was 5,626 F., and at Atlanta, Ga., it was 5,052° F. 
 
 The average mean total effective temperatures for the sections of 
 Texas, Louisiana, and Georgia, as given by the Weather Bureau for a 
 seriesof eleven years, are as follows: Texas, 5,710°; Louisiana, 5,578 ; 
 Georgia, 5,234° F. 
 
 The effect of this decrease in temperature will doubtless be in some 
 measure counteracted by a certain degree of adaptation thereto on 
 Hie part of the weevil, but it still seems probable that in the tempera- 
 ture of Georgia a considerable reduction in the number of generations 
 will be found. The emergence from winter quarters will probable be 
 considerably later than the middle of April. The development of 
 progeny will not be as rapid as has been described for Victoria, Tex., 
 in preceding pages. Furthermore, it seems likely that during the 
 warmest periods the life cycle will require from 22 to 28 days. The 
 consequent limited number of generations in a season will be still 
 further curtailed by the earlier period of hibernation, which it seems 
 will begin as early as the latter part of October or the first of Novem- 
 ber, instead of during December, as was the case during the past t wo 
 years at Victoria. The date of the killing frosts will, in a general 
 way, fix the end of the active season for the weevil, and this will 
 therefore vary considerably from year to year. 
 
104 
 
 T \i:i.k XXVII. — Temperature comparisons of various cotton sections. 
 
 Month. 
 
 Monthly average normal mean for 11 years, 1892-1902. 
 
 Victoria, 
 Tex.,av- 
 
 erage 
 (1902 and 
 
 1903 
 only). 
 
 o pi 
 
 Jane T.").n 
 
 July BO - 
 
 August 80.2 
 
 September I 77.6 
 
 October I 71.6 
 
 November 63. 7 
 
 Average f < >r 6 months. . 74. 8 
 
 Dallas, 
 Tex. 
 
 Shreve- 
 port, La. 
 
 F. 
 
 80.5 
 83.3 
 82.8 
 77.4 
 68.1 
 56.7 
 
 F. 
 
 79. 9 
 32 l 
 
 :: - 
 
 67.1 
 56. 8 
 
 r4.4 
 
 Atlanta. 
 Ga. 
 
 F. 
 78.0 
 80.3 
 79. 2 
 
 70.2 
 62. 6 
 
 57. : S 
 
 71.2 
 
 Texas 
 section. 
 
 F. 
 
 80.6 
 
 88.9 
 
 82.8 
 77.3 
 67.9 
 57.3 
 
 Louisi- 
 ana sec- 
 tion. 
 
 80.1 
 83. 5 
 81.6 
 77.1 
 67. 7 
 58.9 
 
 r4.6 
 
 UA 
 
 Georgia 
 section. 
 
 78. 2 
 80. 1 
 79.0 
 
 74.7 
 64.5 
 58.9 
 
 12. 2 
 
 From these considerations of temperature difference and judging 
 the varying influence as ascertained at Victoria, it seems that the 
 weevil may prove less and less destructive as it spreads to the cooler 
 portions of the cotton belt, though this supposition is likely to be 
 nullified by an ability to adapt itself to new conditions. 
 
 While it must be admitted that nothing, so far as now known, seems 
 certain to prevent the spread of the weevil to any latitude where cotton 
 is now grown, it does seem probable that its control ma}' be more easily 
 accomplished in the more northern portions of the cotton belt than in 
 the Texas area now infested, and since it has been most positively 
 demonstrated that better than the average crop may here be grown 
 in spite of the depredations of the weevil, there would seem to be no 
 special reason for a panic over the future of the cotton crop. Cotton 
 has been and still will be grown in spite of the weevil. The present 
 promise is that those planters who enter the struggle with determina- 
 tion, and who adopt the advanced methods which have proven suc- 
 cessful wherever tried, will realize practically as large a profit from 
 cotton raising in the future as it has been possible to obtain in the 
 past. 
 
 DISEASES. 
 
 Especially in moist breeding jars, weevils often die from what 
 appears to be a bacterial disease. The body contents liquefy, turning 
 to a dark brown in color, and have a putrid odor. Death follows 
 quickly, though not until after putrefaction has begun. The fre- 
 quency with which several weevils died in the same jar at about the 
 same time indicates that this disease may be contagious. It has not 
 been found in the fields, however, and may have been due entirely to 
 abnormal laboratory conditions. 
 
 It is doubtful whether the following observations upon fungus 
 attacks upon weevils should properly be classed with diseases, but as 
 there is a possibility that the attack may have been of this nature, the 
 observations may be given here. 
 
 In July, 19<>2, a lot of squares sent by mail from Calvert, Tex., to 
 Victoria, was so long delayed upon the road that they were very 
 
105 
 
 mold} when received. Thirteen apparently healthy pupae were 
 removed from these moldy squares with the intention of rearing 1 1 m * 
 adults. The pupae were kepi moist, and in a shorl time 5 died, 
 apparently from the attacks of an unknown species of fungus. The 
 remainder were then kept dry, i>ui in spit*' of this precaution 6 more 
 died, only 2 becoming adult. In another Lot of 27 pup®, 5 died, 
 apparently from attacks of the same fungus. 
 
 Specimens of the dead pupae were scut to the pathologist of the 
 Bureau of Plant [ndustry of ili<' Department for determination of the 
 fungus, h was pronounced to be a probably new species of Asper- 
 gillus. As no species of this genus is known to be parasitic, it may 
 be thai the pupae died from some other cause and thai the fungus was 
 entirely saprophytic. The external appearance of Hie fungus so soon 
 after the death of the pupae, the large mortality prevailing, and the 
 known fact thai pupae develop uninjured in the presence of many 
 species of molds leads to the suspicion that it may have had some 
 pari in causing the death of the insects. 
 
 In L894 Prof. ('. II. T. Townsend, while engaged in the study of 
 the boll weevil, found in a field at San Juan Allende, Mexico, a speci- 
 men of a dead pupa which had been attacked by a species of paiasit ic 
 fungus (Cordyceps sp.). As no other cases of attack by this fungus 
 have been reported, its occurrence is probably very rare. 
 
 PARASITES. 
 
 BREEDING OF PARASITES. 
 
 Owing to the importance attached to parasites in the control of 
 many pests, considerable time has been devoted to the rearing of para- 
 sitic enemies of the boll weevil. From the very nature of the habits 
 of the weevil, no perfectly satisfactory method of breeding these para- 
 sites could be devised. The apparatus used was exceedingly simple. 
 Squares which were thought to be infested were picked or gathered 
 in the field, and cleared, so far as was possible, of all that might pro- 
 duce parasites not developed from the weevils. Small lots of these 
 squares were placed in paper bags, each fitting tightly over the open 
 mouth of a glass jar. As both parasites and weevils upon emergence 
 naturally make their way to the light, they could easily be seen in the 
 glass jars and at once removed. Even when thus bred something 
 must be known of the habits of each species of insect produced or of 
 its close allies to determine whether it is really a parasite upon a 
 w^eevil larva, a hyperparasite, or merely a vegetable feeder devel- 
 oped in the decaying square. Many small flies breed in such decaying 
 matter and were caught in the jars, but these must all be acquitted of 
 being parasites upon the weevil. The results are therefore made 
 somewhat uncertain because of the impossibility of isolating the 
 weevil larvae. A condensed summary of the results in breeding 
 parasites through two seasons' work is presented in Table XXVIII. 
 
106 
 
 TABL EC XX VIII . — B reeding of parasites. 
 
 
 Collector. 
 
 
 
 Weevils 
 bred. 
 
 Parasites. 
 
 Locality. 
 
 Date. 
 
 Squares. 
 
 Bracon 
 mellitor. 
 
 Other 
 
 spe- 
 cies. 
 
 Sguarespickedfrom plants 
 
 mill from ground. 
 
 Calvert, Tex 
 
 G.H.Harris 
 
 W.E.Hinds. 
 
 1902. 
 July, August 
 do 
 
 2,566 
 645 
 
 387 
 
 881 
 4(13 
 
 342 
 
 277 
 
 210 
 
 108 
 
 278 
 111 
 251 
 
 120 
 
 3 
 1 
 
 1 
 
 10 
 3 
 
 
 45 
 
 1 
 1 
 
 
 fW.D. Hunter.... 
 JW-E. Hinds 
 
 W.E.Hinds 
 
 do 
 
 J- August 
 
 1903. 
 June 
 
 
 
 
 
 
 Do 
 
 July 
 
 1 
 
 Do 
 
 ...do 
 
 August 
 
 July, August 
 
 
 
 Infested squares dried on 
 the plants. 
 
 W.E.Hinds 
 
 
 
 
 Total 
 
 5,548 
 
 1,355 
 
 63 
 
 8 
 
 
 
 
 
 From these observations it appears that 24.4 per cent of the 5,548 
 squares used produced adult weevils, while only 1.3 per cent of the 
 
 total squares contained 
 parasites. Among the 
 parasites obtained, 90 per 
 cent were of the single 
 species Bracon mellitor 
 Say (fig. 4). A single 
 specimen of another un- 
 doubtedly primary para- 
 site , Sigalp li us c 1 1 rcul io / 1 is 
 Fitch, was reared. A few 
 specimens of Catolaccus 
 incertus Ashm. may pos- 
 sibly have come from the 
 weevil larva?, but were 
 more likely hyperpara- 
 sites. According to the 
 authority of Dr. William 
 II. Ashmead, of the 
 United States National 
 Museum, to whom the writer is indebted for the specific determina- 
 tions and also for information about the usual habits of these para- 
 sitic insects, the following species, which were bred from squares, 
 must probably be credited to some other host than the boll weevil: 
 Chalcis coloradensis Cress, and Goniozus platynotce Ashm. were prob- 
 ably upon lepidopterous larva?; Eurytoma sp. and Eupelmus, two 
 spp., usually attack dipterous larva? in galls and a number of speci- 
 mens of a species of Ooencyrtus may have been parasitic upon the 
 eggs of some lepidopteron or hemipteron, but certainly could not 
 have reached the eggs of the weevil. 
 
 Fig. 4. 
 
 -Bracon mellitor, parasite of boll weevil— much 
 enlarged (original). 
 
1<)7 
 
 H la \,-i\ noticeable that the dried squares which were picked from 
 the plants produced by far the largesl part of all the parasites obtained, 
 .'ill' Bquares giving •"> (| parasites. In this lot, therefore, I I per •••■m <>f 
 the total number contained parasites of some kind and 13 per cent 
 were undoubtedly developed from the weevil Larv». Taking all other 
 squares together, 5,286 yielded only L8 primary parasites, or onlj 0.3 
 per cent. 
 
 Previous efforts to breed parasites of the weevil yielded a^ meager 
 results as those which have just been recorded, though they add to 
 the number of species. Iu L894 Prof. C. II. T. Townsend bred, ai 
 Corpus Christ i, Tex., a single specimen of Urosigalphus robustus 
 Ashm., which was in all probability a primary parasite, as was also 
 Bracon dorsata Say, of which 
 Mr. Scli war/ obtained two 
 specimens at Goliad, Tex., in 
 the fall of L895. A specimen 
 of Ewrytoma tylodt rmatis 
 Ashm., also reared by Mr. 
 Townsend, may possibly have 
 had some other host. 
 
 Pedieuloides Vi rvtricosus 
 Newp. — This small mite has 
 been thought by some scien- 
 tists to be the most promising- 
 parasite yet found attacking 
 the weevil. It has been ex- 
 perimented with quite exten- 
 sively by Prof. A. L. Herrera 
 and his assistants of the Mexi- 
 can Commission of Parasi- 
 tology. The mites breed with 
 extreme rapidity, the larvseof 
 wasps being their usual hosts. 
 Both sexes attain full physical 
 
 and sexual maturity while yet within the body of the mother. The 
 males are exceedingly tiny, as are also the females, when they first 
 leave the mother mite. As the females become gravid, however, their 
 abdomens swell to an astonishing size as compared with the rest of 
 the body, being distended by the rapid growth of the young mites 
 (fig. 5). When these are born the mother dies, while the offspring 
 mate, and then immediately begin the search for food. The idea of 
 the Mexican investigators was that these tiny parasites would be able 
 to enter the square through microscopic orifices in the outer layers, 
 and that they would attack and destroy the weevil larva3 and pupae 
 within. Upon his return from a trip to Mexico in the fall of 1902, 
 the senior author brought with him, through the kindness of Pro- 
 
 Fig.").— Enemy of cotton boll weevil, Pedit ruloidU s w /<- 
 tricosvs— much enlarged (adapted from Brucker). 
 
108 
 
 fessor Ilerrera, a supply of the parasites, from which others were 
 reared for experimental work in Texas. 
 
 In the course of these experiments the possibility of the mites 
 attacking larvae, pupa3, or immature adults was tested. The obser- 
 vations made failed to show any positive ability on the part of the 
 IVdiculoides to penetrate the squares, as in only two cases were mites 
 found in them and attacking the larva?. In these two cases it seems 
 entirely possible that the mites may have entered through feeding 
 punctures or some other rupture in the floral envelopes. 
 
 Upon several occasions during the season of 1903 mites were dis- 
 tributed in badly infested cotton fields. Later examinations were 
 carefully made, but they failed to show that the parasites had gained 
 a hold or even that they had attacked the weevils in any stage. 
 
 These mites, if, indeed, they are of the same species as those de- 
 scribed by Newport, are widely distributed and attack, to some 
 extent, quite a large number of insects. If they really possessed the 
 ability to get at the weevil larva? and the predisposition to attack 
 them when they could get to them in preference to other hosts, they 
 should certainly have shown something of these capabilities some- 
 where within the infested area in Texas during the ten years that the 
 weevil has been found there. As no such ability has yet been shown, 
 we doubt that the Pediculoides will ever prove of any value as a par- 
 asite of the weevil in the United States, though it may be more effi- 
 cient in more southern countries. Furthermore, it is said that even 
 where the mites do become established they are so subject to the 
 attacks of small ants that their efficiency becomes largely destroyed. 
 
 Several attempts have been made by agents of this Division to 
 breed parasites of the weevil in localities which must be much nearer 
 its original home than is Texas, but thus far these attempts have 
 proven as fruitless as have those made in Texas. It seems desirable 
 that this work should be continued so as to give a more complete 
 knowledge of all the parasites of the weevil in its native home. 
 
 These results show how insignificant is the part which insect para- 
 sites play in the problem of controlling the boll weevil in Texas. 
 The thorough protection of all immature stages of the weevil by 
 several layers of vegetable matter and the protection of the adult by 
 its hard, closely fitting, chitinous, external plates renders very small 
 the hope that any parasite will ever become an efficient factor in 
 controlling this dangerous pest. 
 
 There is at present, therefore, no promise of any considerable 
 assistance in the control of the weevil by any parasite now known. 
 Because of its peculiar life history the weevil is unusually exempt 
 from the attacks of parasites. Even should one be found which 
 could attack the weevil in some stage, it would probably still fail to 
 be an efficient means of control, because, from the very nature of its 
 parasitic habits, it is bound to be behind the weevil both in the point 
 
 
L09 
 
 of d umbers and in the time of its activity. While such parasites 
 might Berve to decrease the numbers of the wreevil, everj larva thai 
 becomes parasitized has already done its damage toa square. 
 
 In spite of the preseul unpromising outlook for the discover} of 
 valuable parasites of the weevil, every effort to find Buoh should i><- 
 made. WTiile earnestly hoping that effective parasites maj yet be 
 discovered or developed, it is folly for planters to neglect <>r delay 
 the adoption of those methods of decreasing wreevil injury which 
 have already proven to be both practical and effective. 
 
 PREDATORY ENEMIES. 
 INSECTS. 
 
 Insects which prey upon the boll weevil appeal- to be even fewer in 
 number of species than are those which are parasitic upon it. The 
 principal enemies of this class are ants, 
 and where common these probably destroy 
 more immature weevils than do the para- 
 sites. They are frequently to be found 
 in squares on the ground in the act of 
 destroying larva 1 or more often pupae. 
 ( Occasionally they have been found enter- 
 ing infested bolls which are yet hanging 
 upon the plants and destroying the pupa', 
 which had become exposed by the prema- 
 t u re cracking open of their cells. In some 
 eases they have been known to destroy 
 young adults which had emerged but not 
 become fully hardened. Several species 
 of ants are concerned in this good work. 
 The most active is a small red ant, Sole- 
 nopsis debUis var. texana Mayer? (fig. 6). 
 Another species belonging to the genus Myrmica also does considerable 
 good. 
 
 Occasionally there may be seen upon cotton plants specimens ol a 
 mantis, or "devil horse," as it is more commonly called. One species 
 only, Stagmomantis limbata Halm., has been carefully tested for its 
 ability to destroy weevils. A male of this species was confined in a 
 breeding cage and supplied with a number of adult weevils. Sev- 
 eral times it was seen to seize a weevil and attempt to eat it, but 
 being unable to break through the hard chitinous plates which ><» 
 closely cover the weevil's body, it gave up the attempt and let the 
 weevil go unharmed. Although kept for some time with weevils in 
 its cage, it never fed upon them, but starved to death in their pres- 
 ence. With the female of this species the case is quite different. 
 One was confined in a cage and supplied with an abundance of wee- 
 
 Fig. 6.— Solenopais debilis var. tex- 
 anal ant enemy of l»oll weevil — 
 much enlarged (original). 
 
110 
 
 vils. It seemed to be more powerful than the male, breaking through 
 
 the weevil's skeleton with apparent ease. On several occasions it 
 was found to eat 8 or 10 weevils a day. During her period of con- 
 finement in the cage she deposited a large batch of eggs, and in the 
 course of about three weeks she destroyed altogether a total of 80 
 weevils. 
 
 Some species of Mantispa also probably devour a few weevils in the 
 field, but the writer has never seen one in the act. 
 
 BIRDS. 
 
 There can be no doubt that birds are exceedingly valuable assist- 
 ants to man in reducing the numbers of many insect pests. In order 
 to determine to what extent they feed upon the boll weevils, it is nec- 
 essary that an extensive study be made of the stomach contents of all 
 birds that may be found in cotton fields. To be at all conclusive 
 such studies must be made in numerous localities and during more 
 than one season. To accomplish this it is deemed advisable to reserve 
 for the present the results of the studj r of the relation of birds to the 
 weevil problem, that a more complete treatment of the question may 
 be made in some future publication. 
 
 METHODS OF COMBATING THE WEEVIL. 
 
 The difficulties in the way of controlling the boll weevil lie as much 
 in its habits and manner of work as in the peculiar industrial condi- 
 tions involved in the production of the staple in the Southern States. 
 The facts that the weevil lives in all stages except the imago within 
 the fruit of the plant, well protected from any poisons that might be 
 applied, and in that stage takes food normally only by inserting its 
 snout within the substance of the plant; that it is remarkably free 
 from parasites or diseases; that it frequently occupies but 14 days for 
 development from egg to adult, and the progeny of a single pair in a 
 season may reach 134,000,000 individuals; that it adapts itself to 
 climatic conditions to the extent that the egg stage alone in Novem- 
 ber may occupy as much time as all the immature stages together in 
 July or August, are factors that combine to make it one of the most 
 difficult insects to control. It is consequently natural that all the 
 investigations of the Division of Entomology have pointed toward 
 the prime importance of cultural methods of controlling the pest. 
 All other methods must involve some direct financial outlay for 
 material or machinery, and are consequently not in accord with 
 labor conditions involved in cotton production in the United States. 
 Moreover, the cultural methods are in keeping with the general tend- 
 ency of cotton culture; that is, to procure an early crop, and at the 
 same time have the great advantage of avoiding damage by a large 
 number of other destructive insects, especially the bollworm. Never- 
 theless, it must not be understood that attention has not been paid 
 
 
1 1 1 
 
 to the investigation of means Looking toward the extermination of 
 the pest. Asa matter of fact, everj suggestion, from the possibility 
 o\' breeding resistant varieties to the use of electricity in destroying 
 the weevil, has been fully investigated. The results have all been 
 negal ive. 
 
 CULTURAL METHODS. 
 
 The cultural method begins with reducing the numbers <>f the pest 
 in the fall by the destruction of the plants as soon as it becomes appar- 
 ent that no more cotton is to be produced. The enormous importance 
 of this procedure is shown by the fact already stated (p. 82) that the 
 late issuing weevils arc the ones which successfully hibernate. Fur- 
 ther strong reasons are given on pages 91 and 92j under the sections 
 " Relations of weevils to top crop" and "Some reasons for the early 
 destruction of stalks." Hosts of weevils may thus be killed, a very 
 small percentage surviving the winter, and in the same operation the 
 ground is better prepared for planting the following season. A large 
 proportion of t he weevils thus destroyed would otherwise pass through 
 the winter successfully and increase the damage to the planted cotton 
 the following season. Wherever the cotton is allowed to stand in the 
 fields in the hope that a top crop may be produced opportunities are 
 furnished for the development of a very large number of weevils. As 
 explained before in this bulletin, the possibility of a top crop has 
 always been exceedingly remote. Wherever the weevil exists it is 
 not a possibility at all. The method, of fall destruction onty involves 
 applying labor that is necessaiy in any case in preparing the land for 
 planting a few months earlier than is the normal practice among 
 cotton planters. It has been the custom to leave the land uncleared 
 until shortly before planting time in the spring. Now, however, this 
 clearing process is necessary as the last step in the production of the 
 preceding crop. This method, as a matter of. fact, is the only practi- 
 cable strictly remedial method that has been devised. 
 
 Simple uprooting of the plants by means of plows, and burning 
 them as soon as sufficiently dry, is very effective; but undoubtedly 
 the most effective way would be to leave a row out of 20 after the gen- 
 eral uprooting has taken place, to serve as a trap. When the weevils 
 have assembled upon these plants they might be killed easily with 
 crude petroleum, as the destruction of the plants at that time would 
 be immaterial. Nevertheless the heaps of drying stalks also act as a 
 trap, and consequently, especially in view of the success that attends 
 the method, the average planter will believe the destruction of all the 
 plants in the field a better plan than any modification of it. 
 
 The remaining portion of the cultural method consists in furthering 
 the advantage gained by fall destruction by bending every effort 
 toward obtaining a crop that will mature before the weevils have had 
 an opportunity to do considerable damage. The most important fac- 
 tors in obtaining an early crop are early planting, selection of a 
 
112 ' 
 
 rapidly growing variety, fertilization, and thorough cultivation. The 
 success of the planter will be indirect proportion to the extent to 
 which he is able to combine these essentials. Early planting of early 
 varieties will be found to be of comparatively little avail unless fol- 
 lowed by thorough cultivation, and in case of unavoidably delayed 
 planting the best hope of the planter will be in persistent cultivation. 
 As the details of the cultural method have been dealt with fully in 
 the Farmers' Bulletins of this Department, and as the basis for them 
 in the habits of the weevil Avas fully explained in the preceding pages, 
 it is unnecessary in this connection to more than summarize them : 
 
 (1) Fall destruction. 
 
 (2) Early planting of rapidly maturing varieties. 
 
 (3) Wide spacing, which, besides favoring rapid maturity of the 
 plant, also acts as a remedial measure by allowing the sun to reach 
 the ground and causing the diying up of the squares in which the 
 larva 1 occur. 
 
 (4) Thorough cultivation. 
 
 (5) Fertilization with commercial preparations containing high per- 
 centage of phosphoric acid. 
 
 In addition to this general system that is applicable to all cotton 
 plantations, favorable labor conditions sometimes make it feasible to 
 pick the infested squares by hand. Nothing could be more out of 
 place than to suggest hand picking upon large plantations. Even with 
 convict labor it has been found entirely impracticable. But, never- 
 theless, where a planter has onty a few acres of cotton and there is 
 an abundance of cheap labor, such as that of children, the method 
 has been found very effective. 
 
 FUTILE MEANS. 
 
 The very serious nature of the boll weevil problem is constantly 
 illustrated by the manner in which various useless devices and nos- 
 trums are brought to public attention. At one time it was widely 
 spread about that mineral paint would act as a specific against the 
 weevil. An equally fallacious theory that also received considerable 
 popular attention was to the effect that cotton-seed meal exerted a 
 powerful attraction for the pest. 
 
 Probably the most important useless recommendation has been that 
 of spraying. It was supposed for some time by certain parties that it 
 might be possible to poison weevils economically by attracting them 
 to some sweetened preparation. The experiments detailed on i>ages 52 
 to 56 of this bulletin regarding the attraction of various sweetened 
 substances demonstrate the fallacy of the theory. Even if these sub- 
 stances exerted as much attraction as was supposed, there would be 
 insurmountable difficulties in the application of the method in the 
 field. Spraying of a field crop has never been a success and, unless 
 entirely new methods are eventually perfected, never will be of any 
 practical importance. It is true that it is possible to destroy a cer- 
 
I 1:; 
 
 lain Qumber of weevils in regions where > » - j > i * -• i cotton occurs by 
 ln'.-i\ il\ spraying the earliest plants, bul this method is of immeasur- 
 ably less importance than the simple practice of cultural methods. 
 
 Many attempts have been made to perfect a machine thai will ass is I 
 in the warfare againsl the weevil. They have been designed to poison 
 the insects, to jar them and infested squares from tin- plain and to 
 colled them, to pick the fallen squares from the ground, to kill by 
 fumigation, and to burn all infested material on the ground. The 
 Division of Entomology has carefully investigated the merits of repre- 
 sentatives of all of these classes, beginning in L895 with a square- 
 collecting machine thai had attracted considerable local attention in 
 BeeCounty. CTpto the present time none of these devices have been 
 round to be practicable or to offer any definite hope of being even- 
 tually successful. At one time there was some hope thai a machine 
 designed to pick the squares from the ground by suction mighl be 
 perfected. The experiments, however, have indicated probably in- 
 surmountable difficulties; and an implement concern, after having 
 experimented with the matter fully and after having expended over 
 15,000, lias come to the conclusion that mechanical difficulties will 
 always prevent the perfection of such a machine. If it were not pos- 
 sible to raise cotton profitably without the use of a machine, the situ- 
 ation would be changed materially; but since it is possible to produce 
 the staple without the use of any other means than those which enter 
 into cotton culture everywhere, there seems nohope for these machines. 
 
 BIBLIOGRAPHY. 
 
 This bibliography includes only the more important writings which 
 have been published in permanent form. It does not include the 
 main' hundreds of titles of articles published in newspapers and in 
 popular magazines. 
 
 1843. Bokeman, C. II. — Genera et Species Curculionidum cum Syn- 
 onymia hujus Familiar ed. C. J. Shonherr Vol. V, pt. 2, pp. 
 232-233. 
 
 The original description of Anthonomus grandis. 
 
 1 87 1 . Suffriax, E. — Verzeichniss der von I)v. Gundlach auf der Insel 
 Cuba gesammelten Riisselkafer. Archiv. f. Naturg. XXXVII 
 
 Jahrg. 13, pt. 1, pp. 130-1 31. 
 
 Contains the record of a specimen from Cardenas and one from San Cris- 
 tobal, in Cuba. 
 
 1885. Riley, C. V. — Report of the Commissioner of Agriculture, f. 
 1885, p. 279. 
 
 Contains the sentence ''Another very large species. .1. grandis Boh., we 
 have reared at this Department from dwarfed cotton bolls sent from north- 
 ern Mexico by Dr. Edward Palmer." This is the first published record of 
 the food plant and method of injury of the species. 
 21739— No. 45—04 8 
 
114 
 
 1891. Dietz, W. G. — Revision of the Genera and Species of Antho- 
 nomini inhabiting North America. Trans. Am. Ent. Soc, 
 Vol. XVIII, p. 205. 
 
 The species is here reported from Texas. It has been shown, however, 
 that this was an error. See Insect Life. Vol. VII, p. 273. 
 
 1894. Howard, L. O. — A new Cotton Insect in Texas. Insect Life, 
 
 Vol. VII, p. 273. 
 
 The first authentic account of the occurrence of the species in the United 
 States, and some statements regarding its life history. 
 
 1895. Howard, L. O.— The New Cotton-boll Weevil. Insect Life, 
 
 Vol. VII, p. 281. 
 
 Regarding the importance of the pest and the investigation started by the 
 sending of Mr. C. H. T. Townsend to Texas in December. 1894. 
 
 1805. Towxsexd, C. H. T. — Report on the Mexican Cotton-boll Weevil 
 in Texas (Anthonomus grandis Boh.). Insect Life, Vol. VII, 
 Xo. 4, pp. 295-309, figs. 30, 31. March. 
 
 1S95. Howard, L. O. — The Mexican Cotton-boll Weevil. Circular 
 Dlv. Ent., IT. S. Dept. Agric, Xo. 6 (second series), pp. 5, 
 figs. 1-3, April. 
 
 1895. Rios, J. R. — Aparicion del, "Picudo" en la Laguna. El Pro- 
 
 greso de Mexico, August 15, 1895. 
 
 1896. Howard, L. O. — The Mexican Cotton-boll Weevil, Circular 14, 
 
 Div. Ent., U. S. Dept. Agric. (second series), pp. 8, figs. 1-5. 
 A revision of Circular Xo. 6. 
 
 1897. Howard, L. O.— The Mexican Cotton-boll Weevil, Circular 18, 
 
 Div. Ent., U. S. Dept. Agric. (second series), pp. 8, figs. 1-5. 
 A revision of Circular Xo. 14. It was issued in English. Spanish, and 
 German editions. 
 
 1897. Rios, J. R. — Aparicion del "Picudo" en la Laguna. El Pro- 
 greso de Mexico, Vol. IV, pp. 811-813. 
 A reprint of an article in the same journal for August 15. 1895. 
 
 1897. Ed. Junta de Defensa Contra el "Picudo/' El Progreso de 
 Mexico, Vol. V, pp. 8-9, Octobre 8. 
 
 1897. Ed. El Picudo (Anthonomus grandis Boh.). Documentos ref- 
 erentes a su Existencia en Mexico y a su Invasion in los 
 Estados Unidos del Xorte. Mexico, Oficina Tip. de la Secre- 
 taria de Fomento, pp. 100, figs. 1-5. 
 
 Consists of a few letters from Mexican cotton planters and translations of 
 some of the publications of the Division of Entomology. 
 
 1897. Baeestrier, L. de. — Las Medias precautorias contra las Plagas 
 que asolan a la Agricultural. El Progreso de Mexico, Vol. IV, 
 pp. 575-576, May '22. 
 The author urges the necessitv of some definite action, 
 
1 L5 
 
 L897. Howard, L. O.— The Mexican Cotton-boll Weevil in L897. Cir- 
 cular l>i\. Ent., r. 8. Dept. Agric, No. 27 (second Beries), 
 
 pp. 7. 
 
 L897. Il«>\\ lrd, L. 0.— Insects Affecting the Cotton Plant Farmers' 
 Bulletin, U. S, Dept. Agriculture, No. L7, pp. L6 -':;. ftgs. ~ LI. 
 Reprinted From Bulletin 88, Office of Experimenl Stations, CJ. S. Dept. 
 Agric, pp. 81 1 850. 
 
 L898. ll"\\ \i;i>, L. 0.— Remedial Work against the Mexican Cotton- 
 boll Weevil. Circular Div. Ent., CJ. 8. Dept. Agric, N< 
 (second series), pp. 6. 
 This is supplementary to Circular No, 87. 
 
 L901. Rangel, A. F. — Kstudios preliminares acerca del Picudo del 
 
 Algodon {Insanthonomus grandis I. C. C). Boletin de La 
 
 Comision de Parasitologia Agricola r, No. 3, pp. 93-104, 
 
 PI. IX, and figure. 
 
 Deals with 45 experiments regarding destruction by means of hot air, hot 
 
 water, steam, haplaphyton, and arsenic. 
 
 L9G1, Mally, F. W. — A Preliminary Report of Progress of an Inves- 
 tigation concerning the Life History, Habits, Injuries, and 
 Methods for destroying the Mexican Cotton-boll Weevil 
 (Anthonomous (sic) grandis). Authorized by Special Act of 
 the twenty-sixth Legislature of Texas, pp. 1-30, supplement 
 pp. 35-45. 
 
 1901. Mally, F. W. — The Mexican Cotton-boll Weevil. Farmers' 
 Bulletin, U. S. Dept. Agric, No. 130, pp. 30, figs. 1-4. 
 
 A reprint, with minor corrections, of the preceding, excepting the supple- 
 ment. 
 
 1001. Raxgel, A. F. — Segundo Informe acerca del Picudo del Algo- 
 don {Insanthonomus (/rand is I. C. Cu.). Boletin de la 
 Comision de Parasitologia Agricola, I, Xo. 5, pp. 171—1 7*'». 
 
 1901. Raxgel, A. F. — Cuarto Informe acerca del Picudo del Algodon 
 
 (Insanthonom us grandis I. C. Cu. ). Boletin de la Comision de 
 Parasitologia Agricola, I, No. 7, pp. 245-261, Pis. XVI, XXIII. 
 
 1902. IIudsox, E. II.— The Mexican Boll Weevil (Anflwnomus 
 
 grandis). Farm and Ranch (Texas), Feb. 1, 1902, p. 13, figs. 
 
 1902. Hunter, W. I). — The Present status of the Mexican Cotton- 
 boll Weevil in the United States. Yearbook U. S. Dept. 
 Agric. 1901, pp. 369-380, 1 dg. 
 
 1902. Mally, F. W.— Report on the Boll Weevil. Pp. 70, figs. 3. 
 
 Austin, State Printer. 
 
 1903. HUNTER, W. D.— Methods of Controlling the Boll Weevil (ad- 
 
 vice based on the work of 1902). Farmers' Bull. U. S. Dept. 
 Agric. Xo. 1G3, pp. 1G, figs. 2. January. 
 
11(5 
 
 L903. Sanderson, E. D.— The Mexican Boll Weevil. Circ. 1, Ent. 
 Dept. r lV.\. Agric. Exp. Sta. Press Notes, Vol. V, No. 3, pp. 
 8, figs. 4. February. 
 
 1003. Kill the Boll Weevil. How to Grow Cotton in the Weevil Dis- 
 trict. History of the Pest, its Habits, and the Remedies 
 Plainly Disclosed. Pp. 8, figs. 1. Published by the Executive 
 Committee of the Texas Boll Weevil Convention. 
 
 1903. Champion, G. C. — Biologia Centrali-Americana, Coleopt., Vol. 
 IV, pt. 4, p. 186, PI. XI, figs. 3, 3a. April. 
 
 1903. Save the Cotton Crop. Testimony of Cotton Growers on Boll 
 Weevil. How to Insure the Cotton Crop in the Weevil 
 District. Pp. 16; published by the Executive Committee of 
 the Texas Boll Weevil Convention, Bull. Xo. 2, May. Also 
 published in German under the title, "Rettet die Baumwolle," 
 and in Bohemian under the title, "Zachrante bavlnu." 
 
 1903. Sanderson, E. D. — How to Combat the Mexican Cotton-boll 
 Weevil in Summer and Fall. Circ. 1, Ent. Dept. Tex. Agric. 
 Exp. Sta. Press Xotes, Vol. V, Xo. 1, pp. 4. August 10. 
 
 1903. Improved Cotton Seed for Texas Planting. Published by the 
 Executive Committee of the Texas Boll Weevil Convention, 
 pp. 32. Bull. 4, Xov. 9; revised Xov. 17. 
 
 1903. Morgan, H. A. — The Mexican Cotton-boll Weevil. Circular 
 Xo. 1, La. Agric. Exp. Sta., pp. 10, figs. 3, map 1. Xovember. 
 
 1903. Wilson, James. — Report of the Secretary of Agriculture, 1903. 
 Pp. 102-106 under heading, "Crisis in Cotton Production," 
 deals with the Boll Weevil problem. December. 
 
 1903. Connell, J. H. — Proceedings of the Second Annual Session 
 Texas Cotton Growers' Convention, Dallas, Tex. Pp. 99; 
 many illustrations. December. 
 
 190£. Hunter, W. D. — Information Concerning the Mexican Cotton 
 'boll Weevil. Farmers' Bull. Xo. 189, if. S. Dept. Agric. Pp. 
 1-31; figs. 1-8. February. 
 
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