U. S. DEPARTMENT OF AGRICULTURE, DIVISION OF ENTOMOLOGY— BULLETIN No. 42. L. U. HOWARD, Chief of Division. SOME INSECTS ATTACKING THE STEMS OF GROWING WHEAT, RYE, BARLEY, AND OATS, METHODS OF PREVENTION AND SUPPRESSION. PREPARED UNDER THE DIRECTION OP THE ENTOMOLOGIST, BY K. M. WEBSTER, M. S., Special F^eld Agent. WASHINGTON \ GOVERNMENT PRINTING OFFICE. 1903. U. S. DEPARTMENT OF AGRICULTURE, DIVISION OF ENTOMOLOGY— BULLETIN No. 42. L. O. HOWARD, CHIEl of Division. SOME INSECTS ATTACKING THE STEMS OF GROWING WHEAT, RYE, BARLEY, AND OATS, METHODS OF PREVENTION AND SUPPRESSION. PREPARED UNDER THE DIRECTION OF THE ENTOMOLOGIST, BY F\ IVT. WEBSTER, M. S., Special Field Agent. WASHINGTON: GOVERNMENT PRINTING OFFICE, I903. LETTER OF TRANSMITTAL. United States Department of Agriculture, Division of Entomology, Washington, D. O. , September £5, 1903. Sir: I have the honor to transmit herewith the manuscript of a paper entitled ' ' Some insects attacking the stems of growing wheat, rye, barley, and oats," prepared under my direction b}^ Prof. Francis M. Webster, temporary field agent of the Division of Entomology, and now stationed at Urbana, 111. Professor Webster has acted as field agent of this Division, having received temporary appointment since 1884, with headquarters at the experiment stations of Indiana, Ohio, and Illinois, and is ably qualified for the prosecution of the present work through years of study in the States mentioned of the insects which will be treated. As remarked in the introduction, this paper deals with the injuries committed to small grains b}^ different forms of minute flies, eight species in all, which are generally confused by the average farmer with the Hessian fly. The differences between these various species and their method of attack in comparison with that of the Hessian fly are dul} T pointed out, and many valuable sug- gestions based upon an intimate knowledge of the habits of these insects are made for the mitigation of their ravages. In most instances losses by these insects could be prevented by the simplest of farming practices, as set forth in their proper place. I recommend the publi- cation of this report as Bulletin No. 42 of this Division. The fifteen text figures are necessary for the purposes of illustration, those illus- trating plants having been kindly loaned by the office of Agrostologist. Respectfully, L. O. Howard, Hon. James Wilson, Entomologist and Chief . Secretary of Agriculture. 2 CONTENTS. Page. Introduction 7 The genus Isosoma 9 Dealing with the destructive species outside of the grain iields 11 The greater wheat straw-worm ( Isosoma grande Riley) 14 Previous record of the insect 14 Discovery < >f the summer f< trm 15 Discovery of dimorphism and alternation of generations 16 Riley's name, Isosoma tritici, invalid 17 Life history 17 Oviposition of the spring form {minutum ) 18 Oviposition of the summer form (grandi ) 19 Description 21 Adults of summer form ( Isosoma grande Riley) 21 Larva, pupa, and egg of summer form 21 Adults of spring form ( Tsosoma minutum I 21 Larva and pupa of spring form 21 Natural enemies 22 Preventive and remedial measures - 22 Distribution 23 The joint worm {Isosouki tritici Fitch ) 23 Previous record of the insect 24 Life history 26 Distribution 26 Description 27 Adult female 27 Adult male 27 Natural enemies 27 Remedial and preventive measures 28 Difficulty in recognizing the species 28 The barley straw-worm (Isosoma hordei I Iarns ) 29 Previous records of the insect 29 Life history 31 Effect of the larvae on the plant 31 Description 32 Adult female 32 Adult male 32 Natural enemies 33 Preventive measures 33 The captive Isosoma (Isosohhi captivum How. ) 34 Description 34 Adult female 34 • Adult male 35 3 The genus Isosoma — Continued. Page. Webster's Isosoma (Isosoma websteri How. ) 35 Description of adult female 36 The hairy-faced Isosoma (Isosoma hirtifrons How. ) 36 Description of adult female 37 Isosoma secale Fitch 38 Description 38 Adult female 38 Adult male 38 Fitch's Isosoma (Isosoma fitchii How.) 39 Description ., 39 Adult female 39 Adult male 1 39 The two- winged grain and grass flies ■_ 40 Were probably originally grass feeders 41 Early reports of injuries to grain 42 The greater wheat stem-maggot (Meromyza americana Fitch) 43 Past history of the insect 43 Life history 46 Description 47 Adult fly, egg, larva, and pupa 47 Food plants 47 Selection of food plants by the adults 48 Place and method of oviposition 48 Method and nature of attack 49 Extent of ravages 50 Preventive measures 50 Natural enemies ' 51 The lesser wheat stem-maggot ( Oscinis carbonaria Loew) 51 Life history 52 Food plants 53 Place and method of oviposition 53 Nature of injury '. 53 Extent of ravages 54 Description of adult 54 Close resemblance to Oscinis soror Macq " 55 Description of egg, larva, and pupa 55 Preventive measures 56 Natural enemies 56 The American frit-fly ( Oscinis soror Macq. ) 57 Confusion with other species 57 Depredations in Minnesota 58 Life history 59 Food plants 60 Difficulties in studying habits . 60 Eemedial and preventive measures 61 Description 61 Conclusion 62 ILLUSTRATIONS. Page. Fig 1. Canadian rye grass (Elymus canadensis) 12 2. Virginia rye grass (Elym us virgin irus) 13 3. Greater wheat straw- worm (Isosoma grande Riley), spring generation, form minutum; stages 14 4. Greater wheat straw- worm ( Isosoma grande Riley ) , adult summer form . 14 5. Head of wheat partly destroyed by Isosoma minutum 18 6. Method of opposition of female of summer form (I. grande); b, point in straw where egg is placed 20 7. Pediculoides ventricosus Newp., a mite which destroys the larva 22 8. Isosoma tritici Fitch ; adult of the joint worm 24 9. Effect of joint worm in wheat straw 25 10. Isosoma hordei Harr. ; adult of the barley straw-worm 30 11 . Isosoma captivum How. ; adult 34 12. Isosoma websteri How. ; adult female 35 13. Isosoma hirtifrpns How. ; adult female 37 14. Greater wheat stem-maggot (Meromgza americana Fitch); stages and effect on young wheat plant 44 15. Oscinis soror Macq., stages; d, head of Oscinis carbonaria 52 5 SOME INSECTS ATTACKING THE STEMS OF GROWING WHEAT, RYE, BARLEY, AND OATS. INTRODUCTION. Throughout the United States, where the smaller cereal grains — wheat, rye, barley, and oats — are to any considerable extent cultivated, a multitude of injuries to growing wheat are charged by the average farmer to the Hessian fly; whereas, in many cases these ravages are really the work of insects whose habits differ greatly from those of that insect. Indeed, some of them are not flies at all, and even where the ravages are caused by flies, these ar'e not necessarily the Hessian fly, and the same remedial and preventive measures that are applicable to this notorious wheat pest may not be at all effective against them. In fact, it is with the hope of enabling the farmer, as also the economic student, to distinguish between some of the chief insect enemies of cereal grains, and especially between many of them and the Hessian fly, that this publication has been prepared. In the following pages the author has restricted himself to the con- sideration of two groups of grain -affecting insects, the one composed of true flies, and the other not, though both during their developmental stages live and thrive within the stems of wheat, and to some extent within those of the growing grasses as well. Indeed, as a whole, they were doubtless primarily grass feeders, and their grain-attacking habits, being of more recent origin, brought about by the changed con- ditions of their natural food supply, consequent upon the influences of advancing civilization, may be looked upon as a modification % of their original methods of living. While this variety of food plants, including the wild grasses, as well as the cultivated grains, probably has the effect of more generally diffusing some of these insects, thus rendering serious outbreaks of less frequent occurrence, the other phase of the problem is that though the farmer might exterminate them from his fields, they would still inhabit the grass lands and from there continually send a fresh supply of colonists into his fields to repopulate them. But, again, this has its redeeming features, as it enables the grain grower, in some eases, to meet his enemies in the grasses and then 1 tight them to better advantage to himself than in his cultivated fields. The Hessian fly is 7 8 an exception, as it has yet to be found attacking- the grasses in this country; yet several insects whose injuries in the wheat fields have been charged up to it by the farmer may be destroyed to a greater or less extent by closely pasturing the roadsides and fence corners in summer or burning them over in winter or early spring. The first group of these grain-attacking insects to which attention will be here given is composed of those that are not flies at all in the true sense of the term, but small ant-like creatures, realty related to the ants which they so closely resemble. Their }^oung live within the stems of the smaller cereal grains and grasses, and, though these rarety kill the wheat stems outright, they may either prevent the production of th? kernels or cause these last to shrink and shrivel, thereby greatly reducing them both in weight and market value. These insects are called the grain and grass Isosomas, and their young are the wheat straw- worms and the joint- worms. What is still more surprising, they belong to a group of insects the majority of which are not vegetable feeders, but parasitic on other insects, and it was a long time before entomologists were willing to accept the fact that they were the real depredators and not parasites. This doubt as to the real food habits of these insects had not entirely disappeared up to 1884, when the author proved by successive rearings not only the vegetal habits of one of the species, but also the even more interesting fact of dimorphism and an alternation of generations, showing that what appeared to be two species was really two generations of one of them; but one of the generations, being wingless in the adult stage, renders it the more easily controlled by the farmer through a rotation of crop. a The second group of insects here considered is composed of true flies, and these also are both grain and grass feeders in the larval or maggot stage. All true flies have but two wings, and the maggots have no jaws, but the mouth parts consist of two minute hooks whereby they tear or slightly wound the surface of the tender stems and suck the juices flowing therefrom. The Hessian fly is also a true fly, but its form partakes more of that of the mosquito, while these under con- sideration have very much the form of the common house fly, except that they are smaller, and they are frequently quite differently colored. The maggot of the Hessian fly is larger and more robust than are those of the Oscinids, though shorter and differing in color from those of Meromyza. Judging from my own experience and observation, these insects are much more injurious to the young grain plants. One brood of mag- gots of Meromyza work in the full-grown straw it is true, but, as a rule, the injury at that time is seldom very severe, while the larvae of the Oscinids are rarely found in the full-grown straw, except in the a Reports U. S. Comm. Agr., 1884, pp. 383-387; 1885, pp. 311-315; 1886, pp. 573-574. 9 extreme north, notably in Minnesota, and in Manitoba and the North- west Territories in Canada. The Isosomas do not attack the grain plants in the fall, and thus we have a natural division between the two, which is applied in the discussion of these insects in the following- pages. The Oscinids are not destructive in this country alone, as allied species have long been a serious pest in England, France, Germany, and Sweden. The frit-fly (Oscinisfrit Linn.), is some years especially destructive in Europe. The gout-fly (Chlorops ta&iviopus Meigen) and the wheat bulb-fly {Hylemyia coarctata Fallen) are both more or less injurious to small-grain crops in England. • In the preparation of this bulletin the writer has been greatly aided by Dr. Howard and his corps of assistants, both in the Department of Agriculture and also in the United States National Museum, and by Dr. S. A. Forbes in kindly and promptly placing the notes and collections of the Illinois State Laboratory of Natural History at the author's disposal. The writer is also indebted for specimens to Dr. James Fletcher, entomologist and botanist for the Dominion of Canada, and for similar favors received from Prof. F. L. Washburn, State ento- mologist of Minnesota. THE GENUS ISOSOMA. The grass and grain joint-worm flies belonging to this genus are widely distributed in America, some of the most important ranging from the Atlantic to the Pacific coasts and from Canada southward probably as far as the grains, wheat, rye, and barle}^ are grown. The genus Isosoma is known to inhabit Europe, Africa, Madeira, St. Vincent, Australia, and Tasmania. In Europe it ranges over Russia, Switzerland, Germany, Austria, and Italy. When the insect faunas of Asia and Central and South America come to be better understood, we shall in all probability find that species occur in those countries also. These insects belong to the Chalcididse, a family of parasites whose normal food is other insects in one or more stages of their develop- ment. For a long time entomologists refused to believe that the species of Isosoma and their allies were exceptions to this supposed rule, and Harris firmly believed that Isosoma hordei was a parasite and not the true depredator in barley straw. Dr. Asa Fitch after- wards established the fact of phytophagic habits in /. hordei as well as in several other species, but English and European entomologists were not wholly convinced, at least not all of them, up to as late as 1882. When the writer began the study of grain-infesting Isosoma in 1884, comparatively little was known of the habits of some of our most common species, and the establishing of the fact of dimorphism 3G80— No. 42—05 2 10 and alternation of generations by him in the case of Isosoma tritici Riley, as it was then known, and I. grande was without a parallel, in this genus, and so remains in this country. Among the ten or twelve American species that I have reared, none of the others, so far as I have been able to determine, enter the pupal stage in the fall and winter in that condition^ and thus the greater wheat straw-worm {Iso- soma grande) is one stage in advance of the others in spring, and the spring form, minuta, is developed at the time when other species are entering the pupal stage. This is also the only species that I have not succeeded in rearing from food plants other than wheat, with the j^>ssible exception of Isosoma websteri, which might have been reared from young cheat plants, though I hardly think this probable. The fact that I have only found this latter species in spring, and then only females, is indicative of a dimorphism and alternation of generations; but unless it be an undescribed species reared from stems of Tricusjpis sesleroides, which is very late to mature, being even later than any other species known to me, I do not think such alternation can be connected with any other species that I have studied. On the othei hand, and at the other extreme in the matter of food plants, the Elymus Isosoma {I elymi French), has never been with certainty reared from wheat, though abundantly from the stems of cheat grow- ing among wheat and from Elymus growing along the margins of wheat fields. I also find, much to my surprise, that I have reared Fitch's Isosoma tritici aside from its known food plant, wheat, only from Elymus vir- ginicus. Even where this latter grass and the closely allied E. cana- densis have grown side by side, the joint worm {Isosoma tritici Fitch) has held strictly to the former. The white-spotted Isosoma {I albomaadata Ashmead), perhaps the most closely allied to 7. grande of any of the species known to me, and which we should suppose would more than any other incline to dimorphism and alternation of generations, seems, however, to show no such tendency, and, more- over, I have reared it from both cheat and Elymus virginicus, the life cycle, so far as I have been able to follow it, being parallel with those of Isosoma elymi, I. tritici, and I. hordei. I do not, of course, wish to obscure the possibility of an alternation of generations among these insects, with a different food plant for each generation. On the opposite page is given in tabulated form the food plants of the spe- cies of Isosoma known to attack grains and grasses in North America. . « Should the observations of Dr. Andrew Nichols, given under Isosoma hordei, prove correct, this may in future prove erroneous as to I. grande, unless the latter also attacks barley. — F. M. W. 11 •a £ '3 r-t o s. 2 0) V. - V > * o ■s. 3 p "S. o a g 3 u c £ "3 a 2 be 03 £ o o 1 g 42 2 o X? X? X? a 1 a s o Wheat . . X X? X X X X? X X Y? Rye X X? X? X? Elvmua virginicus X X >; X Elvmus canadensis X Cheat. X X X X - V? • X i 1 DEALING WITH THE DESTRUCTIVE SPECIES OUTSIDE OF THE GRAIN FIELDS. In attempting to control the grain-infesting Isosoma, the practical farmer will, in several ways, find himself at a disadvantage. The very deceptive resemblance of these insects to ants, and also to others actually beneficial, will prevent his readily recognizing them in the fields, even if he were to see them at all, and it is only when, by acci- dent, perhaps, that he finds the worms in the stems of his grain, that he will ordinarily be able to detect their presence. As the develop- ment of the insect takes place entirely within the straw, rarely, except in the case of two species, showing any external effects, much injury may occur to the kernels of grain without his being able to determine the cause. It is, therefore, advantageous to him to know that he ma}^ reduce the chances of injury by careful attention to the uncultivated areas that inevitably surround his cultivated fields. As an illustration of the influence of neglecting uncultivated patches like fence corners and roadsides, and allowing these to become overgrown with the different species of rye grass (Elymus), I give the results of my own rearings of these insects from stems of grasses, taken from two different localities along the Illinois Central Railway. In connection with what is here given, it might be well to call attention to the fact that the grounds within the fences along our more important railways are usually better kept than are similar uncultivated grounds along the highways, to say nothing of the fence corners, borders of open ditches, and similar tracts on the premises of the farmers themselves. The locality from which I secured the greatest number of barley straw- worm flies {Isosoma horde i) is situated about 2 miles north of Champaign, 111. The contour of the ground is such that mowing over in summer is difficult, and burning over in winter, though practical, probably did not seem necessary to the railwa}' people. As a conse- quence, a small tract grew up to the Canadian rye grass (Elymus 12 canadensis, fig. 1), the stems of which literally swarmed with the larvae of this species. It beyond question would have furnished enough adults to have stocked hundreds of acres of barley had it been within reach. The presence of the old stems clearly indicated that the place had been neglected for years, and grass stems of the previous year were filled with punctures where the adults had made their escape. Without anyone knowing it, there was here kept a perpetual nursery for barley straw- worm flies, and though not at present a barley coun- try, it is true, it is easy to see what the effects would be were the sit- uation otherwise and must be elsewhere where this grain is more largely grown. The locality from which I secured the least number of these insects, and, in fact, none of the grain-attacking species at all, is located along the same railway, in the edge of the village of Peotone, 111. Here the topography of the ground along the railway is even worse than that in the Champaign locality, but close proximity to the village rendered more attention to it necessary. I am informed by those living near the place that it is regularly mown off during the latter part of June and again in September. The material used in my breeding experiments was collected August 12 at Champaign and August 21 at Peotone, and, though the Canadian rye grass was much more abundant in the latter locality, and to all out- ward appearances at the time the material was secured offered the joint- worms a far superior place to develop there, yet with ample material I did not obtain a single individual, though in Dekalb County, about 60 miles west of Chicago, where, to my certain knowledge, no wheat or barley has been sown for years, from grass col- Fig. 1.— Canadian rye grass J *i . . , (Eiymus canadensis), (after lected August 20 I reared quite a number or Scribner) - these insects. The Dekalb County material was collected from along the neglected roadsides in the country. I can see no possible explanation of the difference in abundance of the joint- worms in the rye grass secured at Champaign and that secured at Peotone, except the difference in the attention given to mowing off the grass during the summer — the same attention that farmers can without troubJe give to the roadsides, fence corners, and ditch bor- ders on and about their own premises. These things are a part of good husbandry, yet among intelligent farmers I have found the two species of rye grass growing not only by the roadsides, but along the very borders of their wheat fields, in some cases the grass and wheat being intermixed along the extreme edges of the fields of grain. 13 Under much the same conditions I heave reared the greatest numbers of joint-worm Hies, at present known as Tsosoma tritici Fitch, from* the Virginia rye grass (El/ymus virginicus, tig. 2). In this case the grass from which I secured these insects in greatest profusion came from the most neglected roadsides. In the vicinity of the city of Urbana, 111., I secured material from two localities, one quite near the resident quarter, where the city government required the mowing off of weeds and grasses, commencing in June, and the other farther from town, along a neglected bank where the grass was allowed to grow up un- disturbed year after year. From grass stems from the former local- ity I secured almost nothing, while from that coming from the latter locality I obtained enough to show that there was here a constant menace to the wheat fields in the neighborhood. Now, as a matter of fact, there is comparatively little wheat or rye grown in the neighborhood, and until 1 reared these insects from the wild grasses I could not account for their sud- den appearance in the wheat and rye fields, observed and recorded in former years by Professor Forbes and his assistants. What has proven true here has been shown to follow similar conditions elsewhere in both Illinois and Indiana. That is to say, where farmers have allowed these grasses to grow up about their farms year after year under the impression that they were not worth any attention, I have found the insects in abundance, and also find that despite their otherwise good farming, they have probably suffered more or less from the attacks of the two species of destructive Isosoma in their grain, though they may not have observed them or their subtile effects on the kernels of the wheat and rye. I am convinced that there is an element of loss here of which farmers are unaware and the precise effects of which they do not therefore comprehend, yet might if they realized the situation. Fig. 2.- Virg-inia rye grass (Elymus virginicus) (after Scribner) . 14 THE GREATER WHEAT STRAW- WORM. (Isosoma grande Riley. Fig. 3, form minuta; fig. 4, form grande.) PREVIOUS RECORD OF THE INSECT. The history of this species extends back only to 1880, though it was probably for many years confused in wheat with the joint- worm. It sometimes occurs that insects which the sj^stematist can only con- sider distinct prove on thorough study to belong to one and the same Fig. -Greater wheat straw-worm (Isosoma grande Riley), spring generation, form minutum: a, b, larva; /, female; g, fore-wing; h, hind- wing; all much enlarged (from Riley). w species, while, on the other hand, it sometimes occurs that what the systematic entomologist considers the same species prove on investi- gation to be entirety different, and thus the problem of control, if injurious, is either simplified or complicated, as the case may be. However easy it may appear to the farmer, to learn all of the life history of an insect is not unfrequently a matter of no little dif- ficulty. Where we can follow out the life cycle of a species accurately, there is usually found some place or period in its existence when it is more easily con- trolled or destroyed than at any other time, and it often occurs that at the critical point some simple manipulation of his land or his crop, on the part of the farmer, will accomplish wonders. This species seems to offer illustrations of all of these features. Fig. 4. — Greater wheat straw- worm (Isosoma grande Riley) , adult summer form, much enlarged (from Howard). 15 In June, 1880, Mr. J. K. P. Wallace, of Andersonville. Tenn.. sent to Dr. C. V. Riley a number of wheat straws containing larva', with the complaint that nearly every stalk or straw was affected by them, and, as a consequence, the straw was inclined to fall before the grain had fully ripened. Mr. J. G. Barlow, of Cadet, Mo., about this time also complained of a similar trouble in his neighborhood, in sonic cases resulting in nearly a total loss of the crop. In the winter of LssL-82, Dr. Riley was able to rear some 30 adults from these infested straws, and, as he considered the species described by Dr. Fitch only a variety of the barle} T straw-worm (Isosoma hordei Harris), he described the adults obtained from these straws as Ix<>s<>,nx<>m<( tritiei. During the previous few days I had been getting from fields of both wheat and rye in the same locality a much larger Isosoma, possessing fully developed wings, and on May i >( .» a pupa, also too large for I. tritiei, was found in the upper part of a dwarfed wheat plant. In the light of more recent studies we now know that I had three species under observation instead of one. The small individuals found early in the month of April belonged to the spring form of this species, and others were Isosoma websteri, while the larger individuals swept from wheat and rye, later in the month of May, were some of them the summer form (L grande), and others belonged to another species, afterwards described as Isosoma captivum Howard. My field of observation was at this time transferred from Bloomington, 111., to Oxford, Ind. On June 6, in a field of wheat near Oxford, I observed female Iso- somas, seemingly like those taken a few days before in the wheat and rye fields near Bloomington, ovipositing in wheat plants, well up toward the top of the stem, probably between the upper joint and the one next below, although, on account of the head of the wheat having not } T et put forth, it seemed as though the egg was being placed in the 16 upper joint. A large number of these adult females were secured, and these constituted the types upon which the description of Isosoma grande was based. a DISCOVERY OF DIMORPHISM AND ALTERNATION OF GENERATIONS. At harvest I arranged with the owner of the field near Oxford to allow a small area where I had witnessed the oviposition of the female Isosomas to remain uncut, and I afterwards secured these straws, apart being kept out of doors and the remainder kept within doors during the following winter. Some conception of the extent to which these straws were tenanted b}^ the larvae of this species may be gained by the fact that of 90 straws from the same field 81 were infested and con- tained 136 larvae. These straws were cut close to the ground, and, therefore, the contained larvae represented the total number. Of 90 straws as cut b}^ the harvester, there were a far less number of larvae present, only 25 being found in the entire lot, the remainder having been left in the stubble. By October all of the larvae had pupated, and my first adult was obtained December 7 from the lot of straws kept indoors. From this time on till June I continued to secure adults issuing from these straws, but everyone of them were Isosoma tritici Riley. All of the straws were now split open in order to determine whether or not any individuals still remained, but none were found. My first adult from the straws kept out of doors appeared March 23, and others continued to appear up to the first week in April, all, as with the straws kept indoors, being Isosoma tritici Rile}^. These straws were now split open and examined, but there was no trace of Isosoma grande, which I knew had deposited eggs in these very straws. Despite all this, on June 1, in sweeping the grass along the borders of a wheat field at Lafayette, Ind. , only about 20 miles from where I had found them the previous year, 1 captured Isosoma grande, and on the following day found them present in the wheat fields. During the fall of 1885 1 took the precaution to sow a small plat of wheat and so protect it that no insects could reach it. The cover was renewed in spring, and some of the Isosoma tritici emerging from straws taken from the field the previous summer were placed in the inclosure where the young protected wheat plants were grow- ing. The adults were placed on this young wheat April 12, and the utmost care taken to prevent any other insects from reaching them, a The records and material in the files and collections of the State Laboratory of Natural History show that what is probably the larvae of this species was found in abundance in wheat straw in the fields in southern Illinois, in July, 1884, and adults of the summer form (grande) were collected by Mr. Garman, at that time an assistant of Dr. Forbes, in various localities in southern Illinois, during late May and early June, 1884, or just about the time that I began to observe it about Oxford, Ind. 17 and, besides, the fields were closely watched for Tsosoma grande. On June 2, fifty -one days after. I found a female of Isosoma grand* in the inelosure and in the act of ovipositing in the now full-grown wheat plants. Others were observed similarly engaged during the follow- ing fortnight, and when the straw was ripened it was cut oh 1 ' and placed in glass jars. I had thus again reared the one supposed species from the other. During the following winter many adults were reared from these straws, but all were of the one form (/. tritiei Riley), and I had reared the two forms twice from each other, leaving now no further doubt that they were simply two generations of the same insect, besides showing that as the spring generation is without wings and can not fly from one field to another, a simple rotation of crop on the part of farmers would result in keeping the insect so reduced in numbers as to place it out of necessary consideration as a wheat- destroying insect. In all of my own rearings of both forms of this species I did not secure a single male, and of the large number reared at the Depart- ment of Agriculture at Washington, from material furnished by me, but three individuals of this sex were obtained. " riley's name, isosoma tritici. invalid. In a more recent study of these insects, b Dr. L. O. Howard found that the species described by Dr. Fitch as Tsosoma tritici was a valid one. This being the case, Riley's name must no longer be used, and the later one, Isosoma grande, thus covers both. Doctor Howard has given the name mi/nutum to the wingless spring form, and this name will hereafter be used in this paper. LIFE HISTORY. The insect passes the winter in the center of the straw, just above the joint, in the pupal stage. Rarely an adult will emerge in late autumn, but if kept indoors others will appear during December, the most during January, showing that they are ready to appear during the first settled warm weather in spring. In further proof of this, I have found that as the winter advances they require less time indoors in which to develop than if the straws are brought in in December, thus showing that, while subject to all of the influences of winter, they are undergoing a change that carries them nearer to maturity. With the settled spring weather they eat a round hole in the straw and make their way forth. As males are few they rarely pair, if at all, but are ready to begin oviposition as soon as out of the straw. They a Report U. S. Coram. Agr. 1886, p. 573, footnote. & Grass and Grain Joint-worm Flies and their Allies, Tech. Ser. 2, Div. Ent., U. S. Dept. Agr. 3680— No. 42—05 3 18 Fig. 5. — Head of wheat partially de- stroyed by Isosomaminutum (drawn in Division of Entomology). are, except in rare cases, entirely devoid of wings, and migration is therefore out of the question, except for short distances. oviposition of the spring form (mintjtum). At the time that the minute, wingless females that comprise this form appear in spring the young wheat plants are only starting to throw the stem upward, and if one will take the trouble to cut one of them directly through the center, longi- tudinally, he will be able to observe the embryo head not far above the surface of the ground. Pushing its ovipositor through the stem to the center, the mother insect places her egg in the embryo head, which is not only the most vital part of the plant, so far as the f ruitf ulness thereof is concerned, but where her offspring will be in the midst of the most tender and highly nutritious food possible. As a re- sult of this the young head is destroyed and further growth of the stem prevented. In some instances the young larva is itself destroy ed before it has finished its destruc- tion of the head, and a distorted wheat head supported by a dwarfed and weakly stem is the consequence. One of these partly destroyed heads is illustrated in fig. 5. In most cases the stem ceases to grow, withers up, and dies, though usu- ally standing upright, at the height of from 1 to. 6 inches, with the leaves drooping down about the stem, both dead and discolored. In feeding on the young head the larva forms a ceil-like cavity which, owing to the size of the larva and pupa, sometimes takes on a somewhat gall-like appearance, not noticeable except when cut in two. It would seem that the superior article t)f food which nature provides for these lar- vae might to some extent account for the larger and more robust adults which constitute the second or summer brood. The larvae must develop quite rapidly, as, 19 by June 10, nearly all have transformed to the adult summer form {grcmde), which begins to appear about June 1 . reaching its maximum in point of numbers about June 20, though I have found an occasional individual as late as the ^7th of that month. In ovipositing, minutwn seems to prefer the lateral stems in which to place her eggs, thus leaving the central stem unaffected. With the summer form (grande) this selection is reversed and the largest and most thrifty stems are selected. Spots of rank growing, thinly placed grain will suffer worse than the more densely growing areas. OVIPOSITION OF THE SUMMER FORM (GRANDE). Nurtured in the midst of the embryo head, we would naturally look for an adult insect differing somewhat from the one developing from larvae whose food is of a coarser and tougher nature, and in this case, whether as a coincidence or otherwise, we have a much larger insect with fully developed wings, forming in consequence the migratory brood of the species. That these females wander about from field to field is shown by the fact that they may be captured during June by sweeping over the grass lands with an ordinary insect net, such as is used by entomologists for this purpose. The method of oviposition between the spring and summer forms does not differ materially, except as the difference in the conditions of the plant makes slight variations necessary. The former must place her eggs in the very young plant comparatively close to the surface of the ground, while the latter seems to try to get her egg immedi- ately above the uppermost joint of the wheat stem within her reach. At the season of the }^ear when this takes place the upper, and fre- quently the joint next below, is not uncovered by the leaves and sheath, but the majority of the eggs are placed, singly, just above either the second or third joint below the head, and rarely above the upper joint. The significance of this to the farmer is that very few of the larvae hatching from these eggs will be taken away with the straw, but, on the contrary, left in the field in the stubble. If the reverse were the case, and most of the larva' removed with the straw to the barnyard, there to be either run through the stables or similarly util- ized, in most cases hardly an individual would get back into the wheat fields in spring, for it must be remembered that at this period the adults are wingless and incapable of flying. The method of oviposi- tion is shown in fig. 6, ". and the point where the egg is deposited in the straw is shown in figure (3, £, the transverse line showing the track of the ovipositor. To place her egg^ the female takes up her position just above the joint, with her head downward. She then straightens her legs, thus throwing her body away from the stem, at the same time bringing her feet almost directly beneath the body. She now brings the abdomen downward and forward between her legs, much 20 as a bee would do if alighting and instantly stinging an animal. The next move is to let the tip of the abdomen strike the stem and then go back to its proper position, but the tip of the ovipositor does not; on the contrary, it catches on the surface of the stem, directly beneath the body of the insect, and by putting its machinery in motion and drawing the stem toward her she slowly forces the ovipositor into the soft, juicy stem at the point where this is solid and not hollow, as is the case a short distance above and immediately below the joint. The tip of the ovipositor is composed of two flattened plates arranged side by side, the edges of which are sharp, and are propelled with a sort of rotary motion alternating with each other. In this way the ovipositor cuts and drills its way to the center of the stem, and an egg is forced down the interior and left in its proper place in the stem of the plant. The female recovers her ovipositor by again straightening her legs and pushing the plant from her. Only one egg is placed in the same location, though perhaps more than one is placed in the same straw by the same female, but if so they are placed above different joints in the straw. The larvae must mature quickly, for, though pupation does not take place until about October, the stem ripens and becomes tough and woody, wholly unfit for the food of the larvae, within less than a month. It would seem that the mother insect is aware of this, as she invariably selects the greenest and rankest growing plants in the more open spots, where the straw matures the slowest and remains green and juicy the longest. Briefly, then, the insect passes the winter in the stubble — with the exception of the few that have been removed with the straw — in the pupal stage. In late March or during April the spring form (minutum), small, jet-black, ant-like, and with rare exceptions wing- less females, eat their way out of their winter home and seek the young growing wheat plants. The}^ deposit their eggs singly, placing them in the embryo head. These hatch within a few days and the larvae mature and transform to the form grande-, large, robust, also jet-black, with fully developed wings, in late May and the first two- thirds of June. These last are also females, and without pairing they begin to deposit their eggs in the now nearly fully developed straws. The eggs are placed just above the uppermost joint accessible to the female, usually the second or third below the head. But a single egg is deposited in a place, the object of the mother insect seeming to be to get it in the center of the stem in the more or less solid portion a 6. — Method of oviposition of female summer form (Isosoma grande, Riley): a, female inserting her eggs; b, section of wheat stem showing point reached by oviposition (after Riley). Fig. of 21 just above the joint. The eggs, as with those of the spring brood, hatch in a short time, and the larvae reach maturity by the time the straw has become too tough and dry to afford further nutriment. The larva at this time usually gnaws its way down into, or at least partly into, the joint, and without forming cell or cocoon, about October passes into the pupal stage. DESCRIPTION. ADULTS OF SUMMER FORM. (Isosoma gr ancle Riley.) Length of body, 4.2 mm.; expanse, 7.0 mm. Antennae rather more slender and less clavate than in the spring form and but half the length of the thorax. Thorax with the mesonotum slightly more rugulose; wings larger and less hyaline than in the winged specimens of the spring form, with the veins extending to the outer third, the submarginal nearly four times as long as the marginal; legs with the femora less swollen. Abdomen not so long as the thorax, stouter than in the spring form, ovate-acuminate, approaching typical Eurytoma. Less hairy than in the spring form, especially about the legs, the hairs about the abdomen being less numerous, less regular, and shorter. Coloration similar to that of the spring form, but brighter and more highly contrasting, the promotal spot larger and brighter yellow, the pedicel of the antennae yellow, and the femora with a definitely limited suboval yellowish spot below, near the tip, extending two-fifths the length of the femur on front pair, smaller on middle pair, and still shorter and less definite on posterior pair. Larva greenish yellow in color. Average length, 6 mm. ; otherwise of same pro- portions and structure as in spring form." Pupa, average length, 5 mm. Except in larger size and ample wingpads undis- tinguishable from that of the spring form, minutum. Egg of the ordinary ovoid form with pedicel about twice as long as the bulbous part. The apical end is furnished with a distinct hook, perhaps for the purpose of holding the egg in place while the ovipositor is being withdrawn from the plant. ADULTS OF SPRING FORM. (Isosoma minutum. ) Length of body, 2.8 mm. ; expanse of wings, 4 mm. ; greatest width of front wing, 0.7 mm.; antenna 3 , subclavate, three-fourths the length of thorax; whole body (with exception of metanotum, which is finely punctulate) highly polished and sparsely covered with long hairs toward the end of abdomen; abdomen longer than thorax and stouter. Color, pitchy black; scape of antennae, occasionally a small patch on the cheek, mesoscutum, femoro-tibial articulations, coxae above and tarsi (except last joint) tawny; pronotal spot large, oval, and pale yellowish in color; wing veins dusky yellow and extending to beyond middle of wing; submarginal three times as long as marginal; postmarginal very slightly shorter than marginal, and stigmal also shorter than marginal. (See Riley, Am. Nat., 1882, p. 247.) Larva, length, 4.5 mm. ; of the shape indicated in fig. 3; color pale yellow; mouth parts brownish. Antenna- appearing as short two-jointed tubercles. Mandibles with two teeth. Venter furnished with a double longitudinal row of stout bristles, a pair to each joint. Each joint bears also, laterally, a short bristle. Stigma pale, circular; ten pairs, one on each of joints 2 (mesothoracic) to 11. Pupa, jet black without other coloring; smaller than that of summer form. That is to say, the pupae wintering over in the straw and from which the spring form develops is thus to be described; that following the larvae developing in spring is understood to belong to the summer form. « Riley, Ann. Rept. CJ. S. Dept. Agr., 1884, p. 58. 22 NATURAL ENEMIES. Probably the most efficient enemy of this species is a small, slender, four- winged fly, of somewhat brilliant metallic-colored body and yel- low legs. This has a very slight resemblance to an Isosoma, and, indeed, was described as Isosoma allynii, now known as Eupelmus ally nil French. A somewhat similar insect with metallic body and yellow abdomen, Stictonotus isosomatis Riley, is very efficient in destroy- ing the larvae in the straw. Homojpor%is (Semiotellus) chalcidephagus Walsh and beyond a doubt other chalcids are also instrumental in hold- ing it in check. These parasites are all the more efficient as they are double-brooded also, developing in late summer and at once ovipositing in other larvae. There is also an egg parasite that I have reared in connection with Isosoma, but not with certainty from this species. This is Oligosita americana Ashmead MS. As in all cases where I have obtained this there were species involved other than the one under con- sideration, it is obviously impossible to say that it destroys the eggs of this species, but with such regu- larity does it occur in connection with Isosoma in fig. i.^Pedicuioides general that no doubt it preys upon this one with the ventHcoms Newp., a others. When the wheat is harvested the straw is the larva— much frequently, and, in fact, almost invariably, cut off enlarged (after Mar- between joints, thus leaving the larvae, if there are such in the straws at that point, exposed to attack from predaceous insects. The larvae of a small, slender, black and yellow carabid beetle (Leptotrachelus dorsalis Fab.) crawls up, descends into the stubble and devours the Isosoma larvae, but unfor- tunately its taste seems to be too obtuse to allow it to confine itself strictly to Isosoma, and as a consequence it devours parasites as well as host. The mite Pedicidoides {Heteropus) ventricosus (fig. 7) is also an enemy, gaining access to the larvae precisely as with the beetle larvae previously mentioned. PREVENTIVE AND REMEDIAL MEASURES. The fact of the spring brood being almost entirely wingless and therefore unable to fly from field to field places it almost totally at the mercy of the farmer, as he has but to change his crop from one field to another to rid himself of its presence. It is true the summer form can fly about from field to field at will, and it does so, but if the spring brood of adults are left helpless in a field with no wheat plants in which to place their eggs, it will be seen at once that there can be no sum- mer brood emanating from this source. Rotation of crop will as a consequence be sufficient to prevent an overabundance of this species. But there are conditions under which this is not practicable, as in some 23 sections and with some farms tne soil is but little fitted for other crops, and where wheat follows wheat year after year for an indefinite period. Under such conditions, burning the stubble before preparing the ground for the new crop in fall will prove effective. If this burning is delayed until September, many of the parasites will have developed and escaped. The burning can be best carried out by cutting the grain as high as possible, leaving the stubble long. A few days before burning a mower should be run over the field, cutting off' all grass and weeds, which, when dried, will add to the fuel supplied by the stubble. Taking advantage of a favorable wind, the farmer can burn over his field cleanly, thereby not only ridding it of the presence of this pest, but also the Hessian fly, besides burning up much of the seed of foul weeds and grasses. DISTRIBUTION. This species seems to occur throughout the middle belt of country from the Atlantic to the Pacific, wherever wheat is grown as a staple crop. Whether it is single- brooded in the North and is. therefore, in such countries capable of sustaining itself in spring wheat, is not yet known. Having no other known food plant than wheat, it will neces- sarily follow that its range will be restricted to areas of wheat culti- vation, and being double brooded, requires fall wheat in which to develop. The fact of its having been so long confused with what now seems the true joint-worm fly (Isosoma tritici Fitch) renders its actual distribution, as well as the extent of its ravages in the past, somewhat obscure. I found the summer form (grande) in considerable numbers in spring wheat at Lafayette. Ind., June 19, 18i>5, and it is likely that it can breed therein, though fall wheat is necessary for form minutum. THE JOINT-WORM. (Isos&ma tritici Fitch. Fijjrs. S and 9.) I have previously referred to the confusion of Isosoma tritici Fitch with I. hordei Harris, and which was so persistently insisted upon by Walsh and Riley. It was not until 1896 that Dr. Howard succeeded in establishing the fact that this is a valid species, and now we are con- fronted with a long series of complications that can only be safely corrected by carefully rearing both species and studying them anew. Failing entirely in securing sufficient material from wheat in carrying out the investigations upon which this bulletin is based, I feel now very much like letting the insect alone until an opportunity is offered to untangle the knotted skein. Doctor Fitch stated distinctly that the term "joint-worm" was to be applied to the insect attacking wheat, and it was because of the mistake of considering it the same insect as that described by Harris that the name "joint-worm" came to be applied to I. hordei at all; a mistake that belongs neither to Harris nor Fitch, but one that has misled nearly everybody. 24 PREVIOUS RECORD OF THE INSECT. About the year 1848, in central Virginia, throughout the country adjacent to Charlottesville, Albemarle County, and Gordonsville, Orange County, the wheat began to suffer seriously from attack of what was at that time called the joint-worm. In 1851 the wheat in Albemarle County was, much of it, not worth the harvesting. In 1854 the ravages of the pest had become so serious that a " joint- worm convention " was held in Warren ton to devise means for controlling it and preventing, if possible, its further ravages, as by this time it had become almost impossible to raise wheat at all in the infested terri- tory. The action of this convention was to recommend a better sys- tem of cultivation, the use of guano and other fertilizers to promote the rapid growth and early ripening of the grain, and the burning of the stubble after harvest. Fig. 8. — Isosoma tritici Fitch: adult of the joint-worm, much enlarged (from Howard). Looking back to this period, our later-day entomologists can hardly understand how there should have been any difficulty in determining beyond a possible doubt the author of all of this destruction. Doctor Fitch, who, it seems, received some of the growing wheat plants infested with the larvae from that locality, always insisted that he found a cecidomyian larvae inhabiting cells like those occupied by the joint- worm and that these were the true depredator, and, though he continued to stoutly defend his determination, we have yet to discover a Cecido- myia either causing or inhabiting such a cell or gall in the wheat plant. From all that has been since learned relative to these insects it is clear that the ravages were those of this species, with, perhaps, individuals of the preceding species intermixed among them. As a matter of history it may be stated that Doctor Fitch was still unconvinced that the joint-worm, and not a dipterous insect, was responsible for the dam- ite as 1859 he expressed astonishment that he was any Hessian flies from age in Vi unable to rear the same straw from which he reared the joint-worm. Surely the unento- mological farmer might be pardoned for falling- into the same error until, at least, he is placed in possession of some way of distinguishing* them from each other. After finding out beyond question that this is a valid species, that it is the true joint-worm fly attacking wheat and not barley, while Is<>s<>m mm. Head, pronotum, and mesonotum strongly rugulose but not umhilicate-puuctate except toward tip of scutellum, where an occasional umbilicate puncture occurs; metanotum also strongly rugulose, with a faint trace anteriorly of a median longitudinal furrow; metanotal spiracles large and perfectly circular; pronotal spots moderately large and often faint, but plainly dis- cernible from above, sometimes, however, quite bright and distinct, Abdomen longer than thorax, nearly as long as head and thorax together; abdominal segments 4 and 5 together longer than 2, 3 only about half as long as 4, and 5 as long as two preceding united; first funicle joint one-half longer than second; club longer than three preceding funicle joints together. Body slightly but plainly julose except at sides of metanotum, where the fimbria is very obvious. Legs black except at joints, which, with the tarsi, are yellow. Claw of stigmal club given off before the tip. Male. — Length, 2.9 mm.; expanse, 6 mm. Petiole shorter than hind coxa 3 , faintly punctate; flagellum of antemne uniformly pilose, joints well rounded above, not strongly pedicellate; joint 1 three times as long as wide and nearly three times as long as pedicel; none of the funicle joints constricted in the middle; joints 2 and 3 each nearly as long as 1 ; joints 4 and 5 each a little shorter; club plainly divided by a distinct incision into two joints, but the terminal ovate joint is not pedicellate." Howard, Tech. Ser. 2, Div. Ent., U. S. Dep. Agr., pp. 17, 18. Originally described by Fitch. Jour. N. Y. State Agr. Soc, 1859, p. 115. Cited as Isosoma hordei by Walsh, Anier. Ent. and Bot., II, p. 332. Described as Decatoma hasilaris by Provancher, Faun. Ent. Can., II, p. 569. NATURAL ENEMIES. The natural enemies are, with few exceptions, probably the same as with the preceding species, to which this is more closely related than with the one that follows, at least so far as its life history is concerned. In my own rearings I have invariably bred this in connection with I. grande if from wheat straw, or with /. dymi if from grass, so that personally. I am not able to say that certain parasites actually came from /. tritici, though there is no reason for doubting that such was the case. Certain parasites do most certainly confine themselves to particular species of Isosoma. Websterelhis tritici Ashm. has only been reared from this species, as it is now known. An undescribed Isosoma occurs in considerable abundance in the stems of Tricuspid St sli rioides, and from this I have reared a parasite belonging to the genus Toryrnus, but strangely enough this parasite has only been 28 reared from this particular Isosoma, even where the grass infested by its particular host was growing in the midst of Elymus, literally alive with the larvae of three other species of Isosoma. Thus, while some parasites attack all of the species, there are evidently others that restrict themselves to one. ' REMEDIAL AND PREVENTIVE MEASURES. Owing to its possessing wings whereby it is capable of flying readily from one field to another, or breeding in the stems of grasses in the intervening territory, a rotation of crop will be less effective in the case of this species than with the preceding. For the same reason, careful attention to roadsides, borders of fields, and ditches becomes all the more imperative. The burning over of the stubble fields before preparing the ground for wheat again in the fall, or the same treatment of the uncultivated areas above mentioned at any time during winter or early spring will effectually exterminate these insects where these measures are carried out. In the Middle West wheat seldom follows wheat on the same ground for a series of years, the grain being rotated with red clover, which prevents the burning over of the stubble fields in the fall, but does not in any way affect the treatment of grass lands, and if the crop is rotated annually and the borders and waste places attended to there is little likelihood of the farmer suffering greatty from the depredations of this insect. I have invariably found the most serious injuries to occur on thin or poorly fertilized soils or where the land had not been thoroughly prepared before seeding. Probably whatever tends to produce a healthy, vigorous growth of the wheat plant will tend to discourage oviposition b}^ the insect. It is not known that the insect prefers one variety of wheat to another, but the variety with the stoutest straw will probably suffer least from attack. DIFFICULTY IN RECOGNIZING THE SPECIES. I have made no attempt to describe the larva and pupa in their proper place, because I do not believe they can be separated by any descrip- tion from those of the preceding species if in wheat, or those of Isosoma elymi French if in grass. Notwithstanding this the farmer can readily separate them, at the proper season of the year, even,if both ara-presjent in his cultivated fields. After October this species will be in the form of a yellowish white larva in the stubble, while the preceding species will be in the form of a black pupa, both perhaps in the center of the stubble. In spring the larvse of this species will change to a jet black pupa, while those of I. grande will have developed and escaped. So, then, pupae found in the fall will probably belong to the preceding species; those found in spring, if in wheat, to this, and larvse found after October, if in wheat stubble, also to this species. However, 29 too much reliance must not be placed on these distinctions, as there are other supposed species of these insects attacking wheat of whose larva 1 and pupa 1 we know nothing, but with our present knowledge the facts just given are the best that can now be offered the farmer in order to enable him to separate the different main enemies of his grain and receive whatever practical benefit is possible from what information is now available, leaving future studies to throw more light upon his problems. The adults can be easily separated from those of the pre- ceding species by their smaller size, and from the next by their smaller size and the color of the legs, which in /. hordei are honey yellow. The larvae are also smaller than those of the following species and ma}' or may not cause galls and deformities in the straw. The adults of the summer form of the preceding and those of the following species are abroad at the same time as are those of this species during the last days of May and early June. While fig. 9 illustrates the effect of the larvae on a wheat plant, there are so many variations from this that it is at present impossible to separate these two gall-forming species by their effect on the straw. THE BAILEY STRAW-WORM. (Isosoma hordei Harris. Fig. 10.) Up to 1896 this species was confused with the preceding and the term " joint- worm" applied thereto. The fact is, Harris seems not to have given this name to his species at all, but on the other hand Doc- tor Fitch applied it to his I. tritici, and it was owing to the confusion of these two insects that the name became misapplied, and 1 have here given Harris's species the name "barley straw- worm," in accordance with the name hordei. PREVIOUS RECORDS OF THE INSECT. Of all of our described species of Isosoma this was the earliest known and was for many years supposed to be the only species infest- ing cultivated grains or, in fact, inhabiting this country, as it was con- sidered a parasite on the real depredator, presumed to be some kind of a two-winged fly, and was actually described by Dr. W. T. Harris in 1830 as a parasite, under the name Ichneumon hordei/ 1 Doctor Harris certainly seems to have been aware of the fact that as early as 1821 Mr. James Worth, of Sharon, Bucks County, Pa., found larvae clearly belonging to some species of Isosoma affecting the culms of wheat i; near the root, where they caused enlargements of the stem;" 6 and in 1823, Mr. Joseph E. Muse, of Cambridge (Eastern Shore), Md., reared an insect, also from wheat, which he termed a a New England Farmer, July 28, 1830; Ins. Mass., 1841, pp. 434-487. b American Farmer, vol. 4, p. 394. 30 \ ^<^ "Tenthredo," whose larvae, as he stated, " burrow within the stems and feed upon them." a Doctor Harris, in the edition of 1841 of his Insects of Massachusetts, page 431, refers to the statement of Dr. Andrew Nichols, of Danvers, who stated that worms found in his barley straw were about one-tenth of an inch in length and of a yel- low or straw color, and that in the month of November they appeared to have passed into the chrysalis state, but living through winter unchanged in the straw. The insects referred to by Mr. Worth, of Pennsylvania, and Mr. Muse, of Maryland, might quite probably have been Isosoma tritici Fitch, but if the one referred to by Doctor Nichols was an Isosoma at all it was certainly I. grande, as that is the only species attacking grain that is known to pupate in the fall. Thus it will be seen that it is not easy to determine just what Harris might have included as belonging to his I. hordei, though he nowhere states that it was ever obtained from any other than barley straw; hence the name, Jwrdei, applied to it. It is interesting to know that specimens labeled in his handwriting "Para- sitic in barley, June 15, 1830," are still in the museum of the Boston Society of Natural His- tory, so that there can be no mistake in the identity of the insect described. Even in the edition of his Insects of Massachusetts, of 1841, Harris makes no mention of his species having been found affecting wheat. In the edition of 1852 he relates that about eight }^ears before children sleeping on straw beds in Cam- bridge, Mass. , had been bitten by these insects and the annoyance" had been so great that the beds, both straw and ticks, had been burned. Now people do not use barley straw for such domestic purposes, nor in fact do they use wheat straw as a rule, but oat straw. As Doctor Harris does not enlighten us as to what kind of straw it was from which the insects annoying the children came, we still have no direct proof that this species was ever known in connection with wheat straw. About 1852 there appeared a similar trouble in the barley in cen- tral New York, and though Doctor Fitch described it as a distinct species under the name Eurytoma fulvipesf we now know that it was «Loc. cit., vol. 5, p. 113. 6 Jour. N. Y. Agricultural Soc, Vol. IX, p. 115. Fig. 10. — Isosoma hordei Harris: adult of the barley straw-worm (from Howard). 81 Isosoma hordel. This last outbreak in central New York appears to have been rather widespread and disastrous, for in 1858 Hon. George Geddes, president of the State Agricultural Society, stated that while formerly a yield of -io bushels of barley to the acre was expected, they could not at that time rely upon more than 20, and unless relief came barley growing, on account of the attack of this pest, would have to be abandoned.'' There was a local outbreak of this species in Ontario, Canada, in 1867-68, and observed at Wakeman, Chagrin Falls, and Barry, Ohio; Indiantown, Cuckoo, and Paynes, Va. ; Albany, X. Y. ; Canada West (William Couper); Ottawa, Canada; and Urbana, Carbondale, and Marshall, 111. So far it has not been reported from the Pacific coast States. Doctor Fitch confined this species to the insect reared by Harris in Massachusetts, and the one working the injuries in central New York as Isosoma fulvipes, both of which are now known to belong to h<>x<>nt