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 UBRAR^ 
 
 Technical Series, No. 16, Part I. (FT ATE PLANT BOARC^ 
 
 U. S. DEPARTMENT OF AGRICULTURE, 
 
 BTJRE^^TJ OF EISTTOMIOLOG-^^. 
 
 L. O. HOV/ARD, Entomologist and Chief of Bureau. 
 
 PAPERS ON COCCID.E OR SCALE INSECTS. 
 
 THE NATIONAL 
 COLLECTION OF COCCIDT:. 
 
 By C. L. MARLA TT, M, S., 
 
 Entoinolog if<t and A^sl^tant Chief of Bureau, 
 
 Issued April 23, 1908. 
 
 ■A^^ GOVERNMENT PRINTING OFFICE, 
 
 WASHINGTON; 
 
 PRIN ' 
 
 1908. 
 
 I 
 
:?i:'.i^^;^"-V.^^^<^'^ v---:Vs.>^- ■^:^'>: 
 
CONTENTS 
 
 Page. 
 
 Historical summary 1 
 
 Recent work of the Bureau 4: 
 
 Preservation of material 5 
 
 The slide collection 5 
 
 Recent additions and present status ■ 6 
 
 Methods of study 7 
 
 The work of the future 9 
 
 A plea for the deposit of types 10 
 
 III 
 
Digitized by the Internet Archive 
 in 2013 
 
 http://archive.org/details/papersoncoccidaeOOunit 
 
U. S. D. A., B. E. Tech. Ser. 16, Pt T, Issued April 23. 1908. 
 
 PAPERS ON COCCID.E OR SCALE INSECTS. 
 
 THE NATIONAL COLLECTION OF COCCID^. 
 
 By C. L. Marlatt, M. S., 
 Entomologist and Assistant Chief of Bureau. 
 
 The collection of scale insects or Coccidse, accumulated chiefly 
 through the agency of the Bureau of Entomology of the U. S. De- 
 partment of Agriculture and forming a part of the national collec- 
 tion of insects, is undoubtedly the most valuable and complete in 
 existence. This has come from the early interest of the Bureau in 
 the subject through the work of Prof. J. H. Comstock, and as a result 
 of the generosity of many of the describers of new species of later 
 years in depositing types or cotypes in the National Collection. It 
 may not be out of place, therefore, to give a brief historical summary 
 of the National Collection of Coccida% together with a description 
 of its present condition, an account of the methods of installation 
 and preservation of material, and a numerical statement of species 
 and types represented. 
 
 HISTORICAL SUMMARY. 
 
 The knowledge in America of this important group of insects was 
 very scant prior to 1880. During that year Prof. eJ. Henry Comstock, 
 then Entomologist of the Department of Agriculture, in the course of 
 an investigation of the insects injurious to orange trees, begun the 
 previous year, noted that the greater part of the insect injury to citrus 
 fruits was due to scale insects. This led him to make, during 1880, a 
 particular study of the family Coccidae. broadening the inquiry to 
 include the study of all scale insects affecting cultivated plants in the 
 United States. Professor Comstock personally collected many south- 
 ern species in a trip through Florida in January and February, 1880, 
 and during the following summer spent three months in the fruit- 
 growing sections of California and Utah investigating the subject and 
 
 1 
 
2 PAPERS OX COCCIDiE OR SCALE INSECTS. 
 
 collecting scale insects. He Avas assisted also by several of his col- 
 leagues in the office, notably Dr. L. O. Howard and Mr. Theo. Per- 
 gande. The results of this work appeared as Part II of his Annual 
 Report for 1880, in a paper on scale insects, which included descrip- 
 tions of most of the Coccidse then in the collection of the U. S. Depart- 
 ment of Agriculture, lack of space preventing the description of all 
 the species which had been collected up to that time. Some 4:5 species 
 are listed and described in this report, more than half of which were 
 new to science. Previous to this only about 30 species had been de- 
 scribed by American writers, the majority of which are to be credited 
 to Dr. Asa Fitch. Most of the species referred to in Comstock's 
 report were figured, and these figures mark the beginning of really 
 careful scientific drawings of Coccid?p, and have since been standard 
 illustrations of the si:)ecies concerned. 
 
 Doctor Howard, while assisting Professor Comstock in the study 
 of Coccida\ took up particularly the subject of the chalcidid para- 
 sites of these insects, and presented as Part III of Professor Com- 
 stock's report a paper entitled " Report on the Parasites of the 
 Coccida^ in the Collection of this Department." This was the begin- 
 ning of Doctor Howard's work on chalcidid j^arasites and led to his 
 becoming the world's authority on the subject. Hoav little was known 
 of these parasites i:)revious to the publication of this paper is shown 
 by the fact that, with four or five exceptions, the species described 
 and figured were new to science. 
 
 Professor Comstock retired from the position of Entomologist in 
 1881, but published in Professor Riley's Report for that year a short 
 illustrated article on Lac Insects, describing three new species. He 
 also gave a brief article on methods of controlling scale insects. A 
 much more important article on remedies for scale insects of the 
 orange, by Mr. H. G. Hubbard, is published in the same report. In 
 this paper some very good work is recorded and some of the more 
 important modern methods of control are given first exploitation. 
 
 Professor Comstock's report on Coccida? in the Department Report 
 of 1880, as already indicated, was incomplete and did not include all 
 of the species collected. His final paper occupied the principal por- 
 tion of the. Second Report of the Department of Entomology of the 
 Cornell University Experiment Station, published in 1883. This 
 jDaper is a brief monograph of the subfamily DiasiDinse as repre- 
 sented in the fauna of Xorth America, together with notes on species 
 not at that time observed in the United States. Several new species 
 are described in this report, and the latter concludes with a list of 
 the American nondiaspine scale insects. 
 
 This practically concluded Professor Comstock's work on Coc- 
 cidae, and for a long period thereafter the systematic study of this 
 important group of insects practically ceased in this country. The 
 
THE NATIONAL COLLECTION OF COCCID.E. 6 
 
 Department Collection contained types or cotypes representing prac- 
 tically all of Comstock's work, and examples of the known species 
 collected by him, and Mr. Theo. Pergande undertook, during the 
 years following 1880, to identify the material which was sent to the 
 Department by comparison with named material in the collection. 
 Mr. Pergande's work during this period was of great value to the 
 Bureau and to the entomologists in this country, but necessarily 
 much that came in could not be identified, and there was a large 
 accumulation of unnamed material representing in part old species 
 and in part species new to science. 
 
 Mr. H. G. Hubbard, Avho has already been referred to as having 
 published an important paper on remedies for Coccida? in the Annual 
 Report of the Department for 1881, continued his investigation of 
 orange insects and the means of controlling them, at Crescent City, 
 Fla., as an agent of the Department of Agriculture, and published in 
 1885 his excellent report entitled '' Insects Atfecting the Orange.'' 
 This represented nearly four years' study and experiment, and dealt 
 very largely with the common scale enemies of the orange. Mr. Hub- 
 bard's interest in scale insects, aroused in this study, continued, 
 although he published nothing noteworthy afterwards on the subject. 
 It was, however, his intention to bring out a new and thoroughly 
 revised edition of his Orange Insects, and to take up in connection 
 with it a study of the classification of Coccida^; but his untimely 
 death prevented the accomplishment of this task. 
 
 About 1891 Prof. T. D. A. Cockerell began to collect and study 
 the Coccidie of Jamaica, where he was then stationed. For some 
 years much of his material came to this office for determination, but 
 in a short time he became familiar with the subject, and ultimately 
 the world's best authority in the group, and for a period of several 
 years much of the new material coming to the Department was sent 
 to him for determination and description. Professor Cockerell had 
 in the meantime accepted a position in the New Mexico Agricultural 
 College, and his collections and descriptions of Coccidse were enriched 
 by the inclusion of mau}^ new southwestern species as well as by 
 material which came to him from all quarters of the world. Very 
 fortunately his close cooperation and sympathy with the Bureau of 
 Entomolog}^ and interest in the National Collection led him to deposit 
 his types in Washington, thus very greatly enriching the local collec- 
 tion. Professor Cockerell, while diminishing ver}^ much his activity 
 in this group in later years, has retained his interest. During his 
 most active decade his publications on Coccida? were voluminous, 
 much exceeding the work of any other investigators in this field with 
 the possible exception of Signoret and Maskell. In connection with 
 this Bureau he published several j^apers, notably his bulletin on the 
 
4 PAPERS ON COCCIDJE OK SCALE INSECTS. 
 
 San Jose scale and its nearest allies," and, through the Smithsonian 
 Institution,^ papers on the food plants of scale insects,^ directions for 
 collecting and preserving scale insects,^ and geographical distribution 
 of scale insects.*^ 
 
 RECENT WORK OF THE BUREAU. 
 
 The resumption of active study of Coccida^ in connection with the 
 Department of Agriculture began in the early ninetias, partly as a 
 result of the interest aroused by the San Jose scale and the necessity 
 of being able to determine at once and authoritatively all material 
 which was coming in supposedly representing this new and danger- 
 ous species. It proved, in other words, impracticable to be dependent 
 for such determinations on specialists at a distance. Mr. Pergande, 
 who had had charge of the coccid collections, had his time so fully 
 taken up with other lines of investigation, notably the subjects of 
 Aphididoe and Formicida^ that he could not keep up with the rapidly 
 increasing collection and literature in Coccidae. To meet the need 
 and following the incentive of an old interest the writer therefore 
 took as his special field in systematic entomology the subject of 
 Coccidae. A season spent in studying orange insects in southern Cali- 
 fornia accentuated his interest in the subject, and general charge 
 of the Department collections in this family was assumed by him in 
 1900, and a thorough reorganization of the collection and notes was 
 then begun. Before this work had j)r()gTesse(l very far it was inter- 
 rupted for more than a year by a trip to the Orient, in which, how- 
 ever, the scale insects were the special object of study and collection. 
 
 During the twenty years which had elapsed since the work of Com- 
 stock, a great mass of material had accunnilated, most of it preserved 
 under very bad conditions, and more than half of it unidentified. It 
 was no small undertaking to bring all tliis mass into order, and in 
 this Avork the writer was assisted (hiring a number of j^ears by Messrs. 
 J. Kotinsky and E. R. Sasscer. 
 
 The enormous increase in the number of scale insects, and the 
 amount of technical work necessary to determine the validit}' of spe- 
 cies and to identify new material, made it early evident that it would 
 be impossible for the writer to keep the whole subject as his own 
 field, and in January, 1905, Mr. J. G. Sanders was appointed an 
 assistant in the Bureau and became the writer's colleague in the study 
 of Coccid?e, the important field of the nondiaspine scale insects, to- 
 gether with the collections and notes, being turned over to him un- 
 reservedly. Mr. Sanders is also charged with the very important 
 
 « Tech. Ser. G, Div. Ent., U. S. Dept. Agric, 1897. 
 
 » Proc. V. S. Nat. Miis., XIX, No 1122, pp. 725-785, 1897. 
 
 <^ Bui. 39, Part L, U. S. Nat. Miis., 1897. 
 
 ^ Proc. U. S. Nat. Mus., XXIl, No. 1026, pp. 615-G25, 1895. 
 
THE NATIONAL COLLECTION OF COCCIDJi]. 5 
 
 inspection and quarantine work of the new importations made by 
 the Department, and in this field has detected and prevented the 
 introduction of a number of new scale insects which probably would 
 have made very destructive records if established in this country. 
 
 PRESERVATION OF MATERIAL. 
 
 The first effort was to arrange for the proper preservation of the 
 type and other material, and a modification of the system followed 
 by Green was adopted — namely, the inclosing of material in strongly 
 made pasteboard boxes, following a definite unit of length and 
 breadth, 3 by 2 inches, so that they can be arranged in five columns 
 in the standard insect draAver which has been in use in the U. S. 
 National Museum ; « these boxes vary in depth, however, to accomo- 
 date different quantities of material. All type and valuable material, 
 in fact all material not in large quantity, is further protected by being 
 first folded in squares of lens paper to retain any loose scales or insects. 
 By this system the bulk of the collection Avas enormously reduced 
 and loss of valuable specimens obviated. This system presents also 
 the great convenience that additions may be made with the same facil- 
 ity as in a card catalogue. 
 
 Special card labels suitable to the nature of the collection were 
 secured from the Library Bureau. These are of different colors to 
 indicate respectively the genus, the valid species and varieties, and 
 the typical material of the species reduced to synonymy. 
 
 THE SLIDE COLLECTION. 
 
 The slide preparations of the different species had become very 
 extensive, and now comprise fully 10,000 slides, relating to more 
 than a thousand sj^ecies. A new system of storage for slide material 
 Avas devised, folloAving the plan of the ordinary card catalogue cabi- 
 net.'^ The older systems of slide storage had proA^ed to be very un- 
 satisfactory for so large a collection representing so many different 
 species. None of the older sj^stems Avas sufficiently elastic or alloAved 
 easy systematic classification, but required card indexes and the con- 
 sultation of many different slide boxes to get together material repre- 
 senting a single subject. This led the Avriter to devise a cabinet in 
 Avhich the slides could be filed on the card index plan. To enable 
 a slide to be thus stored a special euA^elope or jacket is provided for 
 each slide. This jacket is made of strong manila paper and but 
 little larger than the standard slide size (slide 1 by 3 inches, jacket 
 li by 3i inches), affords an opportunity for sufficient labeling, and 
 
 "The insect drawers since then adopted by the National Museum, and in- 
 tended for pinned insects, are somewhat shallower than those first used. 
 & See Science, Dec. 30, 1904, p. 925. 
 
b PAPERS ON COCCID.E OR SCALE INSECTS. 
 
 can be filed exactly as an index card. The cabinet follows the general 
 plan of a library card index, is of five drawers of three partitions 
 each, and holds upward of 2,000 slides. Guide cards were devised to 
 correspond with the slide envelope, and have on their lower edge an 
 extended lip perforated for the countersunk retaining rod which 
 runs just below the level of the slides. This rod holds the guide cards 
 and gives additional security to the slides, which remain steadily in 
 l^lace by their own weight. Each cabinet is arranged with a lock 
 which fastens all five drawers. The latter have the retaining device 
 SO that there is no danger of pulling them entirely out and spilling 
 their contents. The envelopes, however, give such protection to the 
 slides that the latter will not break even from falling some distance, 
 and. furthermore, they j^rotect the slides entirely from dust. The 
 slide cabinets, envelopes, and guide cards are all made by the Library 
 Bureau at very reasonable cost. The slide jackets cost about $2 a 
 thousand, and the cabinets are but little more expensive than the ordi- 
 nary index case. 
 
 This system of storing slides allows for additions indefinitely in 
 exact classification, with as minute and accurate subdivisions as may 
 be necessary. It has now been in use some five years and has given 
 complete satisfaction. The work of consulting the slides and han- 
 dling the material is reduced at least two-thirds, and consultation is 
 so easy that it increases the usefulness of the slide collection many 
 times. 
 
 The cabinet described here in some detail is suitable for dry balsam 
 mounts, and in the preparation of slides of Coccidae the mount, as 
 soon as prepared, is dried over an alcohol flame for a few seconds, 
 wdien it can be put at once into the jacket. In any case where the 
 slide can not be thus dried it must be laid in a horizontal position 
 until the balsam has become thoroughly hardened. Once thoroughly 
 dried, the intense heat of Washington summers does not result in any 
 softening or attachment of the slide to the inclosing jacket. 
 
 A card catalogue has been made of all the material which has come 
 to the Department, and the accumulated notes have been systemat- 
 ically arranged so that they are available for instant reference. This 
 work has been done whenever time was available, and has often been 
 interrupted for weeks or months together, but has now resulted in 
 the collection, notes, and records being in exceptional order and in 
 shape for study by the specialist with the greatest economy of time. 
 
 RECENT ADDITIONS AND PRESENT STATUS. 
 
 The deposit of the types of Professor Cockerell's new species repre- 
 sent the most important additions since Comstock's time. Following 
 this commendable example, most of the other workers in this group 
 
THE NATIONAL COLLECTION OF COCCIDiE. 7 
 
 in this country liave given their types, or at least cotypes, to the Na- 
 tional Collection. Among this material are the species descrihed by 
 Newell, King, Sanders, Tinsley, Johnson,, Townsend, Cooley, Cole- 
 man, and 'Woglum. Cotypes of the greater number of Green's ori- 
 ental species have also been most kindly presented by him to the Na- 
 tional Collection, making a large and very valuable addition. Co- 
 typical or authentic material representing man}^ of the new species 
 of other foreign w^orkers in the family has been received in exchange 
 or by gift, including a considerable percentage of Maskell's species 
 and those of later students, notably Hempel. 
 
 The collection now includes, besides much unidentified material, 
 representatives of 1,072 species of Coccidee, of which 81G are types or 
 cotypes. Of these 366 belong to the subfamily Diaspinse, Avith 293 
 types; and 706 to the non-diaspine scales, with 523 t3q3es. The de- 
 scribed Coccidse of the world now reach a total of nearly 1,600, but 
 of these, from the critical studies which have been in progress now 
 for several years, it seems likely that at least one-third will fall as 
 synonyms, leaving perhaps a thousand valid species. A correspond- 
 ing proportion of the type and other material in the National Collec- 
 tion of Coccidse will fall as synonyms. Nevertheless, the figures given 
 indicate a collection of extraordinary richness and value in its accumu- 
 lation of species and types. In working out synonymy the type 
 specimens of the synonyms, together with the material referred to 
 these synonj^ms by the describers or later workers of authority, are 
 kept together, so that they can be easily referred to should any ques- 
 tion arise as to their status. 
 
 METHODS OF STUDY. 
 
 A very large amount of laborious preliminary Avork has been done 
 which makes no showing, but in the course of this work those Avho are 
 actively conducting it have gained such a familiarity with the subject 
 and so broad an acquaintance with the different genera that it should 
 now be possible for them to monograph the material far more sat- 
 isfactorily and accurately than ever before. The opportunity now 
 had for comparison of types leads necessarily to the discovery of a 
 large amount of synonymy, and the task of weighing and definitely 
 ascertaining the status of older work is now in progress and repre- 
 sents the most difficult part of the undertaking, although a necessar}^ 
 preliminary to the description of new species and the monographing 
 of genera. 
 
 In attempting to make determinations from published descriptions 
 the inadequacy of the characterizations Avas at once felt, through no 
 fault, hoAveA'er, of the early describers, Avho folloAved the customary 
 methods of the time, just as the descriptions of this day may similarly 
 
8 PAPERS ON COCCID.E OR SCALE INSECTS. 
 
 prove to be inadequate fifty years from iio\v. The principal diffi- 
 culty, however, was that many structural features of the insect were 
 not mentioned in the descriptions, and hence a systematic arrange- 
 ment from descriptions Avas impossible, or, if attempted, very faulty. 
 To give a standard for comparisons of descriptions, the writer has 
 drawn up a scheme to be followed which has proved to be a great 
 convenience. It at least insures that no important character is 
 omitted, and the discussion of the different parts in regular order 
 allows an easy comparison of the same characters for different species. 
 Card blanks have been prepared, and following the printed indi- 
 cations the descriptions can be made very readily in abbreviated 
 form and elaborated as fully as necessary for publication. These 
 cards, being of the same size (5 by 8 inches) as the standard note 
 card adopted l)y the Bureau, are filed as a permanent record. The 
 card illustrated below is designed especially for the diaspine scale 
 insects. Some modification of this card is necessary for the non- 
 diaspine species, and Mr. Sanders has worked out such a modifica- 
 tion, also illustrated. It is hoped that the describers of new species 
 of scale insects will follow the order indicated on these cards, so that 
 all future descriptions may be readily comj^ared. 
 
 Order folhnccd in d'.s<rihiii</ I)i<t.si)hiu\ 
 Name : 
 
 Female scale: (Size, shape, density, convexity, color, pellicles, ventral scale, 
 
 situation, etc.). 
 Male scale: (Do.) Male insect: (rn>iniportant). 
 
 Adult female: (Shape, size, color, cbitinization, anterior and niartrinal char- 
 acters, stigmatic pores — if present, relationship). 
 Anal plate: (Shape, size, color, chitinization, etc.). 
 
 Lobe: (No., size, shape, chitinization, i)Osition, etc.). 
 Lateral teeth : (Anterior to lobes and plates). 
 Incisions: (i. e., notches between lobes). 
 
 Paraphyses : (Chitinous thickenings at base of lobes and sometimes mar- 
 ginal beyond lobes). 
 Pl\tes: (No., character, situation). 
 
 Spines: (Position same for all species, as a rule unimportant). 
 Anal opening: (Size, shape, position). Genital opening: (Unim- 
 
 portant). 
 Paragenitals : (No., massed or scattering, etc.). 
 Dorsal pores: (No., size, distribution, etc.). 
 Basal thickenings: (Transverse, broken, rod-like elevations near base of 
 
 plate — dorsal). 
 Ventral thickenings: (Broad areas of slight chitinization extending from 
 tip and longitudinal ridges laterad of vaginal opening). 
 Type: (Dept. No., V. S. Nat. Mus. No., host, locality, coll., date). 
 Note: (Prominent distinguishing characters, relationships, etc.). 
 
THE NATIONAL COLLECTION OF COCCIDiE. 
 Order follotved in descriMng non-didspine Coccidw. 
 
 Name : 
 
 Male: (Scale or puparium ; adult, emergence). 
 
 Female: (Size, shape, color, markings, secretion, maturity, reproduction). 
 
 Derm (cleared) : (Character, size, outline, color, chitinization, pilosity, 
 
 color in KOH). 
 Antennae: (Location, segments, measurements in ,u, formula, hairs). 
 Legs: (Location, development, pilosity, coxa, trochanter, femur, tibia, tar- 
 sus, claw, digitules). 
 Spiracles: (Location, character, pores). 
 
 Pores: (Character, simple or compound; arrangement, dorsal, ventral). 
 Spines — marginal: (Character, length, arrangement). Spiracular : (Char- 
 acter, length, arrangement). 
 HYPOPYGiAL : (Character, number, arrangement). Surface : (Char- 
 acter, length, arrangement). 
 Anal plates: (Shape, size, character, location). 
 
 Set^ — fringe: (Number, location, length). Suuapical : (Number, 
 location, length). 
 apical: (Number, location, length). 
 Thickenings: (Character, locution). 
 Anal ring: (Shape, character, number of hairs). 
 Type: (Host, locality, date, collector). 
 Note: (Prominent distinguishing characters, i)ecu]iarities, relationships, etc.). 
 
 THE WORK OF THE FUTURE. 
 
 It is the intention of the writer and of his colleagues in the study 
 of this family to work out the synonymy of described material which 
 has accumulated, to prepare sj^noptic tables of the different genera, 
 and describe the species which seem to be new to science. These 
 papers will be issued from time to time as parts of the present bulle- 
 tin and of later bulletins of the Technical Series of this Bureau. 
 
 The catalogue and bibliography of Coccidse, started in such a com- 
 preiiensive and thoroughgoing manner by Mrs. Fernald, will be 
 continued in biennial supplements by Mr. »T. G. Sanders, one such 
 supplement having already been issued.^ 
 
 One of the great difficulties in the study of Coccidse has been the 
 inaccessibility of the types of Maskell's many new species, especially 
 as the descriptions and figures were in most cases inadequate. It is 
 a pleasure, therefore, to be able to announce that, through the cour- 
 tesy of Mr. T. W. Kirk, the Department is to be allowed to make a 
 critical examination and study of all of MaskelFs types and other 
 material, which are now^ rnaking their long journey from AVellington, 
 New Zealand, to Washington for this purpose. 
 
 The field of Coccidse is a very large one, and there is plenty of room 
 in it for a considerable number of students, and the National Collec- 
 
 «Tech. Ser. No. 12, Part I, Bur. Ent., U. S. Dept. Agriculture. 190G. 
 
10 PAPEKS ON COCCID.E OR SCALE INSECTS. 
 
 tion is open to anyone who wishes to study or consult it. A good deal 
 of exchange material of value has been accumulated, and exchanges 
 for species not represented in the DejDartment Collection Avill be 
 gladly made. 
 
 A PLEA FOR THE DEPOSIT OF TYPES. 
 
 The Coccida^ present special difficulties in the wa}^ of determination 
 on account of their small size and the necessity of making careful 
 microscopic prej^arations. Furthermore, it is not very practicable 
 to determine material from descriptions only, and it is necessary in 
 most'cases to have type, or accurately identified material, for the pur- 
 pose of comparison. With Coccida^, therefore, more than with other 
 groups of insects, it seems necessary to have some central depot for 
 the deposit of types, where authoritative identifications may be made. 
 It is hoped and urged, therefore, that all American describers of new 
 species will adopt the course of placing type or cotype material in 
 the National Collection, where it will be carefully preserved and be 
 available for study at any time. 
 
 O 
 
UNIVERSITY OF FLORIDA 
 
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