Bulletin OF THE Illinois State Laboratory Natural History Urbana, Ii^linois, U. S. A. STEJPHEN A. FORBES, Ph. D., LI,. D.. Director Vol. XIL March, 1917 Article III. A PRELIMINARY CLASSIFICATION OF DIPTERA, EXCLUSIVE OF PUPIPARA, BASED UPON LARVAL AND PUPAL CHARACTERS, V/ITH KEYS TO IMAGINES IN CERTAIN FAMILIES. PART I. "-"'".'■/i//'-^' --r^/. BY JoHN R. Malloch "-=--^ '<^!}^n^ Mu8i«<<^ Bulletin OF THE Illinois State Laboratory OF Natural History Urbana, Ii^linois, U. S. A. STEPHEN A. FORBES, Ph. D., EE. D. Director Vol. XII. March, 1917 Article III. A PREEIMINARY CEASSIFICATION OF DIPTERA, EXCEUSIVE ~~OF PUPIPARA, BASED UPON EARVAE AND PUPAE CHARACTERS, WITH KEYS TO IMAGINES IN CERTAIN FAMIEIES. PART I. BY John R. Malloch ^' w CONTENTS PAGE Introduction ^^^~i 63 Acknowledgments ^ Habits and habitats of species ^^^ Methods of collection and preservation lo* Economic importance of the order 1^^ Arrangement of families ^ Scope of work 170 177 Characters of the larvae 17^ Suborder Orthorrhapha ^^^ Division Nematocera ^' Division Brachycera Suborder Cyclorrhapha ' Division Acroptera Division Aschiza ^ „g Division Schizophora ^^_^_q Characters of the pupae ^^'^ Suborder Orthorrhapha ^^^ Division Nematocera ^_g Division Brachycera _g Suborder Cyclorrhapha ^ „g Divisions Acroptera, Aschiza, and Schizophora Keys to suborders: — ^jq Larvae Larvae 179 Pupae ^gO Imagines ••••••••• '. ; I .180-407 Suborder Orthorrhapha Keys to divisions: — ^g^ 180 Pupae -^^j^ I"^agines 182-307 Division Nematocera ^g2 Tabular arrangement of families Keys to families : — ^g^ Larvae , gr Pupae jgg If ^g;^^ ;;■;:;:;;::;; 190-245 Tribe Polyneura iqo-24'i Superfamily Tipuloidea 191-207 Family Tipulidae tj" „ Keys to subfamilies Ctenophorinae __ Tipulinae „„,, Principal papers on North American Tipulidae ^"o IV PAGE Family Limnobiiaae 207-238 Keys to subfamilies 208 Cylindrotominae 210 Limnobiinae 212 Pediciinae 216 Limnophilinae 220 Rhamphidiinae 226 Eriopterinae 227 Hexatominae 232 Trichocerinae 234 Papers on the Biology of North American Limnobiidae 238 Family Ptyehopteridae 238-241 Family Rhyphidae 241-245 Tribe Eiicephala 245-291 Superfamily Myeetophiloidea 246-262 Family Bolitophilidae 247-248 Family Mycetophilidae 248-258 Keys to subfamilies 251 Mycetophilinae 251 Sciophilinae 255 Family Sciaridae 258-260 Family Macroceridac 260 Family Platyuridae 260-262 Principal papers on North American Myeetophiloidea 262 Superfamily Culicoidea 263-280 Family Psychodidae 264-274 Papers dealing with Biology of Psychodidae 273 Family Blepharoceridae 274-276 Principal papers on North American Blepharoceridae 276 Family Culicidae 276-279 Keys to subfamilies 278 Some of the more important works on North American Culicidae. . 279 Family Dixidae 279-280 Paper containing account of North American Dixidae 280 Superfamily Chironomoidea 280-291 Family Ceratopogonidae 281-284 Family Chironomidae 284-290 Keys to subfamilies 286 Tanypinae 287 Chironominae 287 Important papers on North American Chironomoidea 290 Family Orphnephilidae 290-291 Tribe Oligoneura 291-305 Superfamily Cecidomyioidea 292-297 Family Cecidomyiidae 293-297 Important papers on North American Cecidomyiidae 297 Superfamily Bibionoidea 297-305 Family Bibionidae 298-300 Important papers on biology of North American species 300 Family Scatopsidae 300-302 Paper on North American Scatopsidae 302 Family Simuliidae 302-305 V PAGE Addenda to Nematoceia 305-307 Trichocerinae 306-307 Division Brachycera 307-407 Tabular arrangement of families 30g Keys to families: — Larvae 308 f "Pa« 310 imagines 312 Tribe Platygenya .314-399 Superfamily Stratiomyioidea 314r-354 Family Stratiomyiidae 315-346 Key to subfamilies 32g Stratiomyiinae 317 Clitellariinae 322 Beridinae 331 Geosarginae 33i Pachygasterinae 334 Xylomyiinae 34O Principal papers on North American Stratiomyiidae 346 Family Xylophagidae , 346-351 Family Coenomyiidae 351-354 Family Acanthomeridae 354 Superfamily Tabanoidea 354-367 Family Tabanidae 355-361 Principal papers dealing with the biology of North American Tabanidae 36j Family Leptidae 362-367 Superfamily Cyrtoidea 368-369 Family Nemestrinidae 368 Family Cyrtidae .368-369 Papers on North American Cyrtidae 369 Superfamily Asiloidea 369-396 Family Mydaidae 370-373 Family Apioceridae 373 Family Asilidae 373-389 Family Bombyliidae 389-396 References to descriptions of larvae and pupae of North American Bombyliidae 395 Superfamily Therevoidea 396-399 Family Therevidae 396-398 Family Scenopinidae 398-399 Tribe Orthogenya 399-407 Superfamily Empididoidea 399-407 Family Empididae 400^03 Papers on the biology of North American Empididae 403 Family Dolichopodidae 403-407 References to papers on the biology of North American and European Dolichopodidae 406-407 Article III. — A Preliminary Classification of Dipt era, exclusive of Pupipara, based upon Larval and Pupal Characters, witJi Keys to Imagines in certain Families. Part I. By J. R. Malloch. Introduction E'conomic and taxonomic entomologists have long felt the need of a synoptic treatise on the immature stages of Diptera. Owing to the added impetus given to the study of this order by the comparatively recent discovery of the economic importance of certain members of the Diptera, the lack of available literature in English dealing with the larvae and pupae has been considerably emphasized. It is not the intention of the writer to attempt a definition of the larval and pupal characters that may be depended upon invariably for the separation of all the families of the order; a simple presentation of the main fea- tures involved in the differentiation of the families, genera, and spe- cies available to him is all that is attempted. It may be that these characters will in the main, with necessary modifications, prove of fundamental importance; but even if later they must needs be rele- gated to the category of things that have been they will at least have served the purpose for which they were intended — the identification of a number of important economic groups — and also constitute step- ping-stones to the firmer ground that can be reached only by a more extended knowledge of the larvae and pupae, and by means of patient and intelligent comparative examination of a larger amount of ma- terial than is now^ at my command. I have been recjuested by several of my entomological colleagues to undertake the task of presenting analytical keys to the immature stages of Diptera. but for lack of material that would add to the infor- mation alreadv published I have hitherto refrained from doing so. I have been steadilv acquiring material, however, for over two years, which, taken in conjunction with material previously in the collection here and that kindly loaned me, probably includes more examples of immature stages of Diptera as a basis for classification than have been brought together elsewhere in the United States. It is, more- over, my opinion that when any entomologist has a considerable amount of additional information upon any phase of a subject it is 162 incumbent upon him, in the interest of his fellow workers, to publish not only his new data, be they new species or life histories, but inci- dentally to link up with his data such facts already published as have a direct bearing upon the subject in hand. It undoubtedly takes valu- able time to make a comparative description of a new species, and where several species in a genus require to be described it necessarily means considerable work to the describer to make a synoptic key to the whole genus as well as to give a description of each of the new species. But when one considers that the time so spent is infinitesimal as compared with that saved to subsequent workers who would other- wise have to puzzle over descriptions in order to discover the differ- entiating characters, it is evident that synopses and comparative de- scriptions are not onlv useful but shtnild be regarded as indispensable in scientific work. It is not with the intention of assisting the narrow specialist that this paper is written ; the purpose is to enable the observant student of nature and the economic entomologist to recognize those forms that often come to their notice and thus obviate the frequent delays and discouragements in obtaining information through other channels. If this object is attained, even in a small measure, science will have gained some advantage and the author will be satisfied. An effort has been made in the general discussions, and particu- larly in connection with life histories, to avoid the use of pedantic terminology, as the writer is of the opinion that except in formal de- scriptions clarity of expression can be attained and conciseness com- passed by the use of language that is understood by the non-entomo- logical reader, much of the terminology and phraseology incessantly cropping out in entomological publications being due either to the training or the personal whim of the writers. This paper deals primarily with Illinois species, most of the material used having been collected in the state by the various mem- bers of the staff of the State Entomologist's Office or that of the State Laboratory of Natural History. In a few cases, however, I have used cxtralimital material belonging to our collections, and have also bor- rowed examples of either larvae or of pupae, or of both, which were not obtained in Illinois, in order to ascertain by an examination of the specimens information not included in previously published de- scriptions that would enable me to complete, as far as possible, data upon certain genera or species. The classification adopted is essentially that used by Brauer in 1883*; but in detail I have not accepted his arrangement, nor have I *Denkschr. k. Akad. Wissenseh., Wien, math.-naturw. CI., 1883, pp. 1-100. 163 used his anatomical nomenclature, for, as has already been pointed out by Lundbeck in his "Diptera Danica", Brauer has erred in this paper in the interpretation of different parts of both larvae and pupae. These misinterpretations are not emphasized herein, as the present writer believes that in undertaking original v^ork such errors are likely to occur, and that in viewing the results of the efforts of authors we ought to adopt a perspective that permits a correct appreciation of the difficulties under which the work was done. By this means we shall arrive at an estimate of the infinitesimal nature of existing blemishes in comparison with the immense advantages afforded to succeeding workers by a perusal of the author's published results. The present paper is presented without any foolish assumption of infallibility, and, as already stated, with a view to adding to the knowledge we already possess of the early stages of North American Diptera. In order to keep the size of the paper within as small a compass as possible, descriptions of species published by the writer in previous papers are not reproduced, but citations are uniformly given to facili- tate reference to them. acknowli:dgmenTs I have to acknowledge the assistance rendered me in this study by the loan or gift of material as follows: from Dr. E. P. Felt, State Entomologist of New York; from W. L. McAfee, of the U. S. Bureau of Biological Survey; from J. J. Davis and J. A. Hyslop, of the U. S. Bureau of Entomology ; from C. W. Johnson, of the Boston Society of Natural History ; and from Dr. R. D-. Glasgow, of the University of Illinois. In 1890-91 Dr. S. A. Forbes obtained a large amount of material from the streams and lakes in Yellowstone National Park, some of which represents genera and species of Diptera not in our collections from Illinois, and these have been used as a basis for con- tributory descriptions. Most of the material from the Illinois River which I have studied in this connection was collected by Mr. C. A. Hart, and some of it was used by him in preparing his paper on the Entomology of the Illinois River*. Several of the species discussed or described were obtained by W. P. Flint and D. K. McMillan in the course of their field work for the State Entomologist's office. HABITS AND HABITATS OF SPECIES Under family headings and very frequently in the discussion of genera I have given notes upon the habits of larvae and imagines, *Bull. ni. state Lab. Nat. Hist., Vol. 4, Art. VI. (1895) 1-64 while in the case of species that I have reared the notes furnish data upon the habitat. This makes unnecessary preHminary details on these points. In fact the Diptera have such a variety of habits in the larval and imaginal stages, and are so generally distributed, that one might be pardoned if he were to dismiss the subject with the laconic remark, "omnivorous and omnipresent". METHODS OF COLLECTION AND PRESERVATION It is necessary, in my opinion, in papers of this nature to give some general directions regarding methods of collecting and, as a part of collecting, rearing species. For the ordinary collecting of forms that frequent manure, de- caying wood, fungi, and mud or comparatively dry earth, as well as phvtophagous species, the best temporary receptacle is a small round tin box about an inch and a half in diameter and three fourths of an inch deep. Dealers in entomological supplies have these for sale, and thev may be obtained with a paper-covered lid, upon the surface of which necessary data may be written. Many species may be reared to maturity in these boxes, the principal objection to this course being that it is not possible to learn whether the flies have emerged without C'pening the box, and frequently the specimen escapes upon the remov- al of the lid. I have had verv satisfactory results with rearing-cages consist- ing of Petri dishes, the upper dish fitting over the lower when inverted. These cages, especially in the spring, proved alt that were required to produce imagines from the larvae of Empididae, Xylophagidae, Syrphidae, and many other families. Aquatic species may be put in Mason fruit-jars or in small bottles, a convenient size of the latter being two-ounce. If not too tightly corked, specimens may be kept in such receptacles over night, but I find it best to use a cotton stopper instead, of a cork unless while carrying the material in from the field. Many species, in fact most of tlie smaller forms, may be successfullv reared in the two-ounce bottles, but I prefer to remove them during the pupal stage, or just before they transform to that stage, to a two-dram vial containing a little water and fitted with a cotton stopper. If transferred before transforming to the pupa the larval skin may be more easily found than in the larger bottle. A mistake frequently made by entomologists in preserving larvae is to put the live specimens into 85% alcohol. This course almost in- variably results in a shrinking of the skin and consequently seriously 165 impairs the value of the specimens. In order to procure the best re- sults in the case of soft-bodied specimens it is especially necessary that the examples be placed at first in water, which should gradually be brought to the boiling point, or near it, and then set to cool. If the water is allowed to boil violently it often results in a distortion or over-expansion of the specimens. Upon removal from the cool water place the specimens in 25% alcohol to remain six or eight hours; next transfer them to 50% strength, in which they should remain twenty- four hours, — after which treatment the larvae may safely be trans- ferred to 85% alcohol,- in which they should be kept. Pupal exuvia that have the integument chitinized may be pre- served dry, but even such forms must be placed in alcohol if the imago has not emerged, as they shrink very much when preserved dry. I have succeeded in obtaining presentable specimens from com- pletely dried-out larval and pupal exuvia by boiling them in water. A larva or a pupa after drying out is rarely restored to its original form except by much patient work; but exuvia, even months after they have dried out, invariably recover their form when boiled. The head parts are generally easily traceable in larval exuvia, but in preserved larvae, especially of Brachycera and Cyclorrhapha, in which the head is retracted, dissection must be resorted to in order to get at the internal structures. I have had some success in ascertain- ing these details when I did not wish to cut up the specimen, by boiling it in 10% potash; but this is a tedious operation, especially if the specimen is a large one, and I prefer to expedite matters by cutting off the anterior two thoracic segments^-caudad of which the cephalic skeleton does not extend— which may readily be cleared so that dissec- tion is possible in a few minutes. The larger species have such heavily chitinized opaque heads that they are not good objects for slide mounts, but the smaller ones should invariably be mounted in Canada balsam. It is always necessary that some system of cross-reference be used for slide, vial, and imago in order to facilitate reference. More detailed information upon methods of mounting specimens is 2:iven in mv article on the Chironomidae of Illinois.* ECONOMIC IMPORTANCE OF THE ORDER No Other order of insects equals the Diptera in diversity of habits in larval and imaginal stages. Many of the families are largely bene- ficial, but unfortunately the good done by them is counterbalanced by *Bul]. 111. State Lab. Nat. Hist., Vol. 10, Art. VI. (1915) 166 the injury inflicted by others. The essentially phytophagous families, that is those families of which the great majority of the species feed upon plants, are very greatly outnumbered by those that are scaven- gers or predaceous or parasitic. If we exclude those that are fungiv- orous, only four families remain that can be classed as preponder- atingly phytophagous — Cecidomyiidae, Trypetidae, Agromyzidae, and Chloropidae ; a few species in these families are predaceous. It must be borne in mind that a phytophagous species is not necessarily in- jurious from the economic standpoint, as many species feed upon and keep in check noxious plants and may therefore be regarded as bene- ficial. It is but a step from the phytophagous to the scavenging habit, and in Drosophilidae we find species that may feed upon Cruci ferae, mining the leaves, or in sap exuding from trees and in vegetable refuse. Few other scavenging Diptera feed upon living plants, the only additional exception known to me being those that are fungivo- rous. There are eight families that may be considered as essentially fungivorous — Macroceridae, Bolitophilidae, Platyuridae, Mycetophili- dae, Sciaridae, Platypezidae, Phoridae, and Drosophilidae. Many of the Sciaridae occur in decaying vegetation, while the habits of Phori- dae are remarkably diverse, some being true entoparasites. The scavengers belong to more than a score of families. In Muscidae all the species scavenge; but in some other families, An- thomyiidae, for example, we find phytophagous and inquiline species, though these are greatly in the minority and the family is essentially one of scavengers. The Sarcophagidae include some species that are true entoparasites, but the great majority are feeders upon decaying animal and vegetable matter. The scavengers are in the great major- ity of cases really beneficial, transforming dead animal and vegetable matter into such forms as can be utilized as food by growing plants. In reducing the bulk of putrefying substances, which, absorbed by the Cfrowinof larvae, are transformed into the bodies of the resultant imagines, they remove what is noxious to man. It is chiefly when scavengers such as the common house-fly contaminate our food by contact, after feeding on foul substances which are impregnated with disease germs, that there is real danger from these insects. Rarely the screw-worm fly and some of the flesh-flies deposit their eggs or larvae in wounds, either on man or on animals, and in this manner produce serious ulcerations, and the larva of the former has been known to cause the death of persons by penetrating the brain, which it entered by way of the nasal passages. The flesh-flies and some other groups sometimes cause mviasis in man, the larvae finding their way into 167 the stomach with food in which the flies have deposited their eggs or larvae and which has not been prepared for consumption by judicious cooking, or carefully examined so as to exclude infested portions. We may class as true parasites nine families, some of which, as Tachinidae (sens, lat.), Dexiidae, and Pipunculidae, are highly bene- ficial, and others, as Gastrophilidae, Hippoboscidae, and Oestridae, are distinctly injurious. The parasites of this order destroy many injuri- ous species of insects, and, next to the parasitic Hymenoptera, con- stitute the most important check upon their increase. Another group of highly beneficial species is that containing the predaceous forms. Two of the families which are to some extent beneficial in the larval stage — Tabanidae, and Culicidae in part — are injurious as imagines, turning their attention from insect larvae, on which they chiefly prey in the early stage, and giving it largely to mammals, including man. This radical change of habit is, however, exceptional, as other predaceous families in this and other orders feed upon insects in both the larval and imaginal stages. Many Syrphidae are aphidophagous as larvae, the greater portion of the species being scavengers, while the imagines are flower-frequenters. The aquatic families, with the exception of the Sciomyzidae and Ephydridae, which are in large part aquatic, belong to the Orthorrha- pha. With the exception of the Mycetophiloidea, which contains five families, the Oligoneura, which contains the Cecidomyiidae, and the families Bibionidae and Scatopsidae, all the families in the division Nematocera are aquatic either wholly or in large part. The aquatic species in the division Brachycera are contained in five families — Leptidae, Stratiomyiidae, Tabanidae, Empididae, and Dolichopodidae. As already indicated in the foregoing general discussion, the larvae of some of these families are predaceous and may justly be considered beneficial ; the others feed upon algae and decaying vegetable matter, and while their presence in water that is intended for drinking pur- poses is undesirable it is not necessarily harmful unless the vessel con- taining them is small and they are numerous enough to foul the water, either with excreta or exuvia. With the exception of some Chiro- nomidae and Culicidae there are few species that frequent reservoirs or cisterns, most of them preferring lakes, ponds, or streams. My information regarding the habits of the order in general leads me to the conclusion that as a whole their beneficial and injuri- ous activities practically offset each other. The fact that there are injurious species which cause great recognized damage, such as the malarial and other disease-bearing mosquitoes and the Hessian fly, very largely outweighs in the mind of the uninformed the benefits — 168 few of which are apparent except to a student of the Diptera — that are directly or indirectly due to the presence of other forms. With advance in a knowledge of the biology of the insects of this order will come a realization that their injurious and beneficial effects are practically balanced. ARRANGEMENT OF FAMILIES In agreement with the method generally used by systematists in zoologica? work, the arrangement of the Diptera is in accordance with the generally accepted theory of evolutionary development, and the families are thus arranged as nearly as possible in their natural sequence from lowest to highest, using as criteria the rather limited data furnished by available life histories, and by a study of imaginal characters ; but in endeavoring to trace affinities the reader must bear in mind that the families included are but the tips of the evolved branches, and not the entire genealogical tree. The hypothetical primi- tive dipterous larva is assumed to have had a complete head with horizontally moving mandibles, the head enclosing the first ganglion ; three thoracic segrnents, the prothoracic with a pair of spiracles ; and ten abdominal segments, the anterior seven, or more, with lateral abdominal spiracles. No larva of this order has yet been discovered which possesses true thoracic legs, but there are many species that have pseudopods or sensory organs upon some of the thoracic seg- ments. This anatomical feature is not accounted as pertaining to a consideration of the phylogeny of the group, as pseudopods are gen- erally regarded as of secondary importance, being developed, partially developed, or absent, in species within the same family. The head is the best single unit available under all circumstances for the purposes of classification, as it is wholly or in large part chitinized and its component parts are accessible for examination eith- er as a composite mass or after dissection, even in alcoholic material, whereas the nerve ganglia and even the tracheal system of alcoholic material are often indistinguishable, and in the case of exuvia entirely lost. The modifications exhibited in the head of the different families are remarkable, and though there are rather abrupt breaks in the chain of ascent as we pass from the Nematocera, with their opposed mandi- bles and complete or almost complete head-capsule, to the Brachycera, with their vertical subparallel mandibles and much reduced head- capsule, and, again, from the higher forms of this group to the Cyclorrhapha, and particularly to the Muscidae, one can trace with considerable probability the line of evolution up to the most highly 169 specialized forms of the present day. In this paper a large series of figures of heads of larvae belonging to all the principal sections is given in order to exemplify the evolutionary phases and, incidentally, to permit the student to judge as to the correctness of the classifica- tion by a comparison of the available data thus presented in the most readily comprehensible manner. An unillustrated discussion of ana- tomical details affords no check on possible misstatement or misin- terpretation by an author or on misconstruction of his words by the student, and to prevent error from one source or another such dis- cussions should be accompanied by figures. Brauer divided the Orthorrhapha into three tribes, Eucephala, Polyneura, and Oligoneura, using the structure of the head as his primary character in separating the groups, Eucephala having the head entire, the others having the head-capsule incomplete posteriorly. Oligoneura has in addition to an incomplete head-capsule vestigial mandibles, a character which separates the tribe from the other two. Brauer's classification has been generally accepted, though several writers have pointed out what they consider to be errors in grouping that result from the application of his rules, and Sharp has gone so far as to suggest that his system has been influenced by his use of dichotomic tables*. Recently a suggestion has been made that as the group Nema- tocera is apparently an unnatural one, containing, as it does, some widely dissimilar families which fall together according to Brauer's classification, we should attach primary importance, not to the struc- ture of the head but to the respiratory systemf. Here, again, an arbitrary attempt has been made to divide the group Nematocera into two tribes, Oligoneura and Polyneura, using the respiratory system as a basis for the division. In some respects the suggestion is an im- provement upon Brauer's system of classification, but even so, the composition of both groups shows some confusion which to my mind proves that the respiratory system is not an ideal character on which to base tribes. In fact the only point clearly shown is that some species of all of the families of Oligoneura, rarely, all species of some of them, are peripneustic and hence assumably primitive structurally, while all species, so far as is known, in Polyneura are amphipneustic. metapneustic, or apneustic. That there are both metapneustic and apneustic forms in Oligoneura of this latter classification, and that several have the lateral abdominal spiracles functionless and may *Verrall 's "British Flies", Vol. 5, p. 31. (1909) tKiiab, in Ann. Ent. Soc. Amer., Vol. 7, 1915, p. 93. 170 therefore be considered as amphipneustic does not seem to have much weight with those who follow this dichotomic arrangement. Perip- neustic larvae occur in Dolichopodidae and vestigial spiracles are pres- ent in some Strayiomyiidae — facts which point, not to the more primi- tive nature of the species possessing these organs but to the persistence of the latter because of their utility in the larval habitat. There must be a further division of the tribes in Diptera, but until we have data upon a larger number of species in the order any proposed subdivision, including that of the present paper, must neces- sarily be merely tentative. I give a figure of a hypothetical genealog- ical tree of Orthorrhapha which illustrates my opinion of the re- lations of the various famiUes (Fig. i). There are defects in the scheme that will probably be obvious to many, and it remains for some future worker to improve on the suggestion here given. The sequence of families in this paper is according to the author's ideas, differing somewhat from that in Williston's "Manual", but subject to amend- ment upon discovery of new data. CuliciJae Ceratopogoiiiilae Orphiiephilidac Rhyphidae Chiroiiornidae Platyiiridae Tipulidae Fig. 1. Hypothetical genealogical tree of Nematocera, illustrating the grouping in this paper. The nervous system as a means of identification may be elimi- nated because of its limited applicability — in preserved material — but we may with little reserve accept as one of the primary indices to affinities the nature of the respiratory system. Insects normally breathe by means of thoracic and abdominal spiracles, and these are found in the adults and in a great majority of the pupae of the Diptera. It is the exception, however, to find them in the larvae, and as a means of 171 identifying those of many of the lower famlHes the absence or pres- ence of the lateral abdominal spiracles is of considerable importance. It is not to be expected that a rule will be discovered as to the absence or presence of these spiracles which will be of invariable applicability to all the families — as at present constituted — in the Nematocera, be- cause we find, from data already in hand, that there appear to be several exceptional genera within the group, and also because perip- neustic larvae occur in much higher families. Taken in conjunction with the structure of the head, however, it is quite possible that the absence or presence of the lateral abdominal spiracles may prove to point to the tracheal system as of primary importance in classification. It must be borne in mind that many families as at present constituted include genera whose larvae have widely different habits, both ter- restrial and aquatic forms occurring at times in closely allied genera and, rarely, within the same genera. In this connection it seems perti- nent to indicate that our system of arrangement is based primarily upon the characters possessed by the imagines, but investigators may, without compunction, remedy errors in the system which, by an ex- amination of the immature stages, are shown to exist. One of the principal characters cited by Brauer for the separation of the Orthorrhapha from the Cyclorrhapha is the nature of the split- ting of the larval skin when the pupa or adult emerges. In the former the skin splits on the dorsum in the shape of a T or + ; whereas in the latter — in which the skin hardens in the last stage to form an en- closing puparium — the splitting is usually transversely across the en- tire dorsum and venter, so that the anterior portion of the puparium comes off cap-like ; or there may be also lateral splits that cause the upper and lower halves of the anterior portion to separate. The lines of dehiscence in Cyclorrhapha puparia are not accidental, but are clearly provided for by weak parts in the membrane. The emergence of the imago in Orthorrhapha is assisted by a slight swelling in the thoracic region, and by movements of the developing wings and hard- ening legs; in Cyclorrhapha the operation is facilitated by the dilation, with air, of a bladder-like sac immediately over the antennae, which, when swollen, forces apart the anterior extremity of the puparium along the lines indicated by the thinner membrane. After emergence the ptilinum, as the bladder-like structure is called, is retracted within an aperture above the antennae and forms a pouch-like cavity. The existence or absence of this peculiar structure in the imagines con- stitutes the primary character for the separation of the two subor- ders— Orthorrhapha being without and Cyclorrhapha with a ptilinum, its presence being indicated by what is called the frontal triangle, im- 172 mediately above the antennae. The families Lonchopteridae, Pipun- culidae, and Platypezidae have a very poorly developed ptilinum or it is undeveloped, but other characters appear to align them with Cyclor- rhapha. In the Orthorrhapha, the imagines of the Nematocera have the antennae usually much elongated and consisting of 7 or more distinct joints; the Brachycera have the antennae consisting of 3 joints, the third being either simple or composed of a number of closely fused ring-like joints having the appearance of an elongated single joint with more or less distinct subdivisions, and there is also, sometimes, a terminal or dorsal arista or style. In the Cyclorrhapha the antenna consists of 3 joints and a terminal or dorsal arista, the second joint in some families being small and entirely or almost entirely enclosed within the very large third, so that the antenna appears to consist of only 2 joints. The wing veins offer a good character for the differ- entiation of the families throughout the order, and being readily acces- sible have been made much use of by taxonomists. The lower forms have a much larger number of longitudinal veins than do the higher, and this seems to point to a coincident reduction of antennal segmenta- tion and wing venation in the evolution of the families of the order. An interesting piece of histological work might be undertaken in connection with the development of the members of the Muscidae and allied families, particularly in the observation of the developmental processes of the head-parts, which are so much reduced in the larvae of these forms. I present in this paper a kev to the imagines of the families of North American Diptera based upon the most recent data available. I have made use of many characters that are not in existing text-books, and in doing so I have simply attempted to put into writing data that many specialists merely carry in their minds. The characters used by Schiner and others for the separation of European families and genera are as a general rule applicable to North American Diptera, but there are many intermediate forms here that do not occur in Europe, and as the keys in use here have largely been copied or adapted from those in use in Europe considerable discretion is rec{uired in locating mem- bers of many families by these keys. The described dipterous fauna of this countr}^ is growing beyond the possibility of competent handling by one individual, and frequently men who are authorities on certain groups are unable to do more than make a guess at the family status of a particular species. I make this explanation in the hope that stu- dents will realize certain facts : that the beginner in the study is facing a stiff task in this order; that the knowledge we possess concerning 173 the order is comparatively meager ; and that I reaHze the possibiHties of error that beset me in the present attempt. scori; OF work In order to keep the size of this paper within a reasonable com- pass I have given generic keys to imagines of those famihes only that are not correctly dealt with in Williston's "Manual of North American Diptera". I have covered the larval and pupal stages of all the groups avail- able to me, depending but rarely upon printed descriptions for differ- entiating characters. In the Orthorrhapha I have succeeded in obtain- ing larvae or pupae, or both, of all the families except Macroceridae, Orphnephilidae, Nemestrinidae, and Apioceridae. The Cyclorrhapha are not so fully represented, but I have a large quantity of material on hand which will serve as a basis for an extensive paper on this group, and this will be published as Part II of the present article. A bibliography of general papers on Diptera will be given at the conclusion of Part II, and papers upon single families will be listed in connection with the text dealing with such families. Characters of the Larvae Suborder ORTHOERHAPHA Division Nematocera Broadly speaking, the dipterous larvae of Brauer's eucephalous group of the Nematocera may be distinguished from those of other Diptera and also from other orders, by the following characters. Head with opposed, usually toothed, mandibles, often, in the aquatic or semiacjuatic forms, with conspicuous brushes on their ex- ternal surfaces; variously constructed antennae which may be barely distinguishable elevations (Mycetophilidae, Sciaridae) or elongated, and consisting of from i to 6 joints and occasionally retractile within the head (Tanypinae) ; well-developed maxillae with i- or 2- jointed palpi ; no well-developed labial palpi ; a more or less chitinized labial plate, or submentum, which is frequently dentate upon its anterior margin ; eyes, when present, indicated by a single or double pigmented area on each side. True legs never present ; prothoracic segment occa- sionally with a pair of pseudopods which may be entirely or partly fused (Chironomidae, Simuliidae) ; anal segment in some cases with a pair of more or less elongated pseudopods which are sometimes armed with curved retractile claws in 2 or more concentric series; 174 abdominal, and occasionally also thoracic, segments sometimes with locomotor spinules in transverse series on portions of their ventral surface ( Mycetophilidae, part) or with pseudopod-Hke elevations or fusiform transverse locomotor areas; respiratory system consisting, in its highest development, of i pair of prothoracic, 7 pairs of ab- dominal, and I pair of anal spiracles, the abdominal pairs not func- tional in some cases (Simuliidae, and Bibionidae and Scatopsidae ?), while in other families they are absent entirely, respiration being car- ried on either by means of the anal spiracles, or by these and the pro- thoracic pair, or by means of blood-gills on the anal segment which are sometimes retractile (Simuliidae, Ceratopogonidae) or perma- nently exserted {Chironomus, part). The acephalous larvae differ very markedly from those of the other group in the reduction of the head-capsule. In Cecidomyiidae the mandibles are vestigial or absent and the posterior portion of the head is poorly defined and membranous, but the larvae may be distin- guished by the presence of 13 segments, in addition to the head; by the lateral abdominal spiracles ; and, usually, in the last instar, by the presence, on the ventral surface of the first and second thoracic seg- ments, of a chitinized plate, generally referred to as the "breast-bone", which is differently shaped in different species and is used by the mature larvae as a means of propulsion in making their leaps after leaving their cells for pupation — in cases where this change is made in the ground. In other larvae of this group there are at most but 12 distinct segments in addition to the head. The reduction of the head-capsule in Tipulidae and Limnobiidae is in the form of a breaking up of the fusion of the component parts posteriorly, the caudal portion of the head thus having the appearance of several slightly diverging rods, the membrane of the prothorax be- ing attached to the head just anterior to the point of divergence. These larvae may be distinguished from those of the higher families of the Brachycera by their opposed, instead of parallel, mandibles. Respira- tion is carried on by means of prothoracic and anal spiracles — the latter supplemented in the ac|uatic forms by retractile blood-gills on the ventral .surface of the last segment — or in some genera by the anal spiracles only. Division Brachycera The larvae of Brachycera are usually readily distinguished by the large maxillae, with their normally conspicuous palpi, between which are the slender labrum and the vertically moving, knife- or sickle-shaped mandibles on each side of it. The antennae are some- times conspicuously elevated but occasionally very short, and the eyes 175 are often readily distinguishable. The head is usually almost fully retractile within the thorax, being permanently exserted in Xylophag- idae, Coenomyiidae, and Stratiomyiidae. Respiration in this group is normally carried on by means of prothoracic and posterior spiracles, the latter being situated upon the ultimate (Stratiomyiidae, Leptidae, etc.), penultimate (Asilidae, Mydaidae, Bombyliidae), or antepenul- timate (Therevidae, Scenopinidae) segments. Some species of perip- neustic Dolichopodidae are an exception to this rule. Many species of Brachycera have on their ventral surface locomotor organs, which may consist of mere transverse irregular swellings (Asilidae, in part, Mydaidae, Bombyliidae, etc.), paired pseudopods (Leptidae, part), or transverse series of spinules (Xylophagidae). Many of the famiHes have conspicuous bristles on the JDody surface, especially on the ventral surface of the thoracic segments and the dorsal and apical surfaces of the anal segment (Asilidae, Mydaidae), or on all of the thoracic and abdominal segments (Xylophagidae, Stratiomyiidae). The normal number of segments in this group is 12, exclusive of the head; but in several families — Tabanidae, Stratiomyiidae, Lep- tidae— only 1 1 are distinguishable. Except in the Stratiomyiidae the pupa is free, that is to say, not enclosed in the indurated larval skin. Rarely the pupa is enclosed in a loose cocoon {Medcterus) or in a very compact one {Drapetis). Suborder CYCLOERHAPHA Division Acroptera This group includes but one family, Lonchopteridae. The sys- tematic position of the group has long been in doubt, but the most recent and comprehensive work upon all stages of the species clearly points to their much closer affinity with the Cyclorrhapha than with the Orthorrhapha. The larvae are distinguishable from those of other Diptera by the fact that they have but 9 well-defined segments in addi- tion to the head. A full discussion of the characters of this group appears under the family heading on a subsequent page. Division Aschiza This group consists of Syrphidae, Pipunculidae, Platypezidae, and Phoridae, according to Brauer. I have before me larvae and puparia of all but Pipunculidae. The cephalopharyngeal skeleton is better developed in this group than in Schizophora, but it is less per- fect than in the most specialized orthorrhaphid larva. In the aphi- 176 dophagous Syrphidae there are upper and lower chitinized mouth- hooks, which consist of two convergent lateral pieces with a V'-shaped anterior extremity and correspond to the pair that are present in Schizophora; but in addition to these there are two to four pairs of small chitinized points or hooks which work horizontally and serve the purpose of grasping prey. The mouth-hooks in Schizophora are not V-shaped and the lower one is absent. These chitinized pieces are less readily distinguishable in the aquatic Syrphidae but are present in modified form, while the mouth-margin is specialized. The an- tennae in all species of the latter family are distinct, usually consisting of a single joint, rarely two, with a pair of short apical processes. The body consists of 12 segments, but the segmentation is indistinct be- cause of the presence of numerous transverse wrinkles or folds in the integument; the surface of the body in most species bears regularly arranged bristles, which are occasionally upon slight elevations and serve to distinguish the different segments. Pseudopod-like structures are often present on ventral abdominal segments, their apices armed with short bristly hairs. Respiration is by means of prothoracic and anal spiracles, the former occasionally doubtfully functional or appar- ently absent, the latter protruding occasionally in a tube-like appen- dage. The larvae of Platypezidae resemble some of the Syi'phidae rather closely, and bear a striking resemblance to the anthomyiid subfamily Fanniinae in having fringed projecting processes on the body seg- ments. The more, elaborate mouth-parts readily separate them from all Anthomyiidae, and also, in my opinion, associate them more closely with Syrphidae than with Phoridae, though Brauer places them with the latter in the tribe Hypocera. The Phoridae are much simpler in general form than most Syr- phidae and all described Platypezidae, possessing, in as far as they are known, no prominent body appendages. The mouth parts are similar to those of the other families of the group in having anteriorly fused mouth-hooks. The larvae are amphipneustic — possessing prc^thoracic and anal spiracles. The transformation to the pupa takes place within the last larval skin. Division Schizophora The larvae of this group, which contains a great majority of the members of this suborder, are readily distinguished from those of any other order by the remarkable reduction of the head, which, when seen laterally, consists of a V- or U-shaped chitinized posterior plate, which has two posteriorly divergent dorsal rods, and, attached to the 177 anterior extremity of this plate, another, smaller plate, which is an- teriorly curved downward and consists of two — rarely one — hooks or mandiijles which are either simple or toothed and operate vertically, scraping or abrading the surface of the larval pabulum so that the food is drawn downward and inward to the mouth cavity. These mouth-hooks, and the entire cephalopharyngeal skeleton, are retracted when the larva is at rest. The respiratory system consists of pro- thoracic and anal spiracles which are connected by means of two large main tracheae, the latter being normally connected by means of a slen- der transverse trachea just behind the prothoracic spiracle, and each sending out upon each segment a stout downwardly and slightly for- wardly directed stout trachea with numerous branches, and, in addi- tion, a smaller trachea, which is an offshoot from the inner surface and is directed almost straight cephalad. The structure of the spira- cles is of great value as a character in the classification of this group. The anterior spiracles are often questionably functional in the aquatic forms, and are sometimes almost or entirely absent in parasitic species, the connection with the air being maintained entirely by means of the posterior pair. Means of locomotion in this group consist of spines on various portions of the thoracic and abdominal segments, with, occasionally, poorly developed pseudopods on the abdominal segments, particularly on the apical segment. Rarely there are elaborate appen- dages upon the thoracic and abdominal segments (Fanniinae), but more frequently the surface of the segments is bare except for the locomotor organs. The larvae transform to the pupal stage within the indurated last larval skin, which is then referred to as the puparium. In this stage characters are frequently developed that are of value in classification; these are dealt with in the section upon characters of the pupae. Characters of the Pupae Suhorder ORTHOEEAPHA Division Nematocera The aquatic members of this group may in the main be separated from those of the Brachycera by their stalked prothoracic respiratory organs, which are occasionallv numerously filamented apically. The few species that are recorded as having these organs sessile may be distinguished from brachycerous pupae by the peculiar recurving of the legs against the ventral surface of the base of the abdomen and the posterior portion of the thorax (Chironomidae). The terrestrial species are distinguishable from brachycerous forms by the very long antennal sheaths which curve over the upper margin of the eyes; 178 whereas in the Brachycera they are either short and inconspicuous or project ahnost in a straight hne across the front of the head, being usually armed with thorns, or they project divergently downward and are frequently armed with strong thorns. The abdomen has usually 7 pairs of lateral spiracles, but in most of the aquatic forms these are not distinguishable. Division Brachycera As mentioned under the previous heading, the pupae of this group very frequently have spines on the antennal sheaths and, in addition, similar spines on protuberances on the face or other portions of the head, and also on the thorax. The prothoracic spiracles are sessile or but slightly elevated except in some Empididae and Dolichopodidae. The abdomen has 7 pairs of lateral spiracles; the segments usually have girdles (1-2) of spines, thorns, or hairs; and the apical segment is usually armed with two or more strong terminal spines or stout processes. Only in the case of the Stratiomyiidae are the pupae en- closed in the last larval skin. The pupae of Coleoptera and Hymenoptera may readily be sepa- rated from those of Diptera by the mandibulate mouth-parts and the presence of four wing-pads, while the latter character will also sepa- rate those of Lepidoptera, though usually the under wings, or posterior wings, are visible only in the form of a narrow strip along the caudal margins of the front pair. Suborder CYCLOEEHAPHA Divisions Acroptera, Aschiza, and Schizophora All the divisions of this suborder may be distinguished by the fact that the pupae are enclosed within the indurated last larval skin. The absence of a well-developed head will readily separate the puparia of this suborder from those of Stratiomyiidae ; in the case of Lonchop- teridae, which resemble the latter family, there is no distinct head, there are only 9 distinct segments, and on the dorsum of the second ab- dominal segment there are horn-like respiratory organs as in Phoridae. The chitinized' structure of the puparia itself will serve to separate them from those of the Cecidomyiidae that pupate under similar con- ditions, the integument of the latter being of a rather flimsy nature. In Lonchopteridae, Syrphidae, Phoridae, and many Muscidae and Anthomyiidae a pair of thoracic respiratory organs are developed upon the first or second abdominal segment in the puparia. These organs do not appear until the pupa is formed, and their mushroom-like sprouting comes rather as a surprise to the observer. 179 Many species that ordinarily make primary, if not exclusive, use of the anal respiratory organs while in the larval staj^e make exclusive use of the prothoracic spiracles in the pupal stag:e. This is noticeably so in species that live under aquatic or semiaquatic conditions. Keys to Suborders EARVAE 1. Head complete, or the posterior portion with deep longitudinal in- cisions ; mandibles moving horizontallv • ORTHORRHAPHA-NEMATOCERA. — Head incomplete, without a strongly developed upper arcuate plate ; mandibles moving vertically 2 2. Maxillae well developed, their palpi distinct; mandibles normally sickle-shaped, not protruded much beyond the apices of the maxil- lae, often extending less than half-way to their apices ; antennae well developed, situated upon the upper surface of a slightly arcuate chitinized dorsal plate ORTHORRHAPHA-BRACHYCERA. — Maxillae poorly developed, their palpi visible only in a few groups ; mandibles short and hook-like, usually capable of protrusion much beyond apices of maxillae if these are present; antennae poorly developed or absent, when present situated upon a membranous surface CYCLORRHAPHA. PUPAE 1. Pupa not enclosed within the indurated last larval skin, or if so the head is distinct as in the larva, or the puparium is slightly flat- tened dorso-ventrally, its texture leathery, not chitinous, and the anterior respiratory organs not distinguishable ; imago, or pupa, emerges through a rectangular split on dorsum of larval skin. . . ORTHORRHAPHA — Pupa enclosed within the indurated last larval skin; head always retracted, the chitinous portion occupying a position on the inner side of the ventral surface of the puparium ; anterior respiratory organs distinct, either protruded from the antero-lateral angles of the cephalic extremity or from dorsum of base of abdomen; imago usually emerges by forcing off the rounded anterior ex- tremity of the puparium in cap-like form, or the dorsal half of the thoracic portion — the lines of cleavage being along the lateral margins to a point at base of abdomen; rarely emergence ia through rectangular splitting of the dorsum of the puparium . . . CYCLORRHAPHA. 180 IMAGINES 1. Antenna consists of a 2-jointed scape — the basal joint usually indis- tinct— and a distinctly segmented flagellum of more than 2 joints ORTHORRHAPHA, pt. — Antenna consists of apparently 2 or 3 joints and, usually, a ter- minal or dorsal arista 2 2. Frontal lunule absent ORTHORRHAPHA, pt. — Frontal lunule present, or if poorly developed or apparently absent there are no distinct cross-veins on disc of wing CYCLORRHAPHA. Suborder ORTHOBEHAPIIA Keys to Divisions LARVAE 1. Head complete, or sometimes incomplete posteriorly; mandibles ab- sent or vestigial in Cecidomyiidae, but the body consisting of 13 segments in addition to the head, in other families mandibles present, moving horizontally or nearly so, their position when at rest being on a horizontal plane, or varying but slightly from it, their apices opposed ; labium usually well developed, in the form of a flat plate with or without dentate anterior margin; larvae frequently peripneustic, the aquatic forms usually with protrusive anal blood-gills NEMATOCERA (p. 182). — Head always incomplete and partly retracted within the prothorax ; mandibles moving vertically, their position when at rest vertical, the apices parallel and directed downward ; labium poorly de- veloped, rarely or never in the form of a fiat plate; larvae nor- mally amphipneustic or metapneustic, very rarely peripneustic, aquatic forms without protrusive anal blood-gills BRACHYCERA (p. 307). PUPAE 1. Head, except in some Cecidomyiidae and a few Tipulidae, without strong thorns ; antennae much elongated, always very distinctly traceable, normally curved well over upper margin of eyes and extending to or beyond base of wing, in some cases almost to apex of wing; thoracic respiratory organs much elongated or sessile; legs of variable length, often extendi)ig to apex of abdomen, rarely slightly longer than wings, in aquatic forms often recurved against base of abdomen ; abdomen in species with short antennae some- times unarmed NEMATOCERA (p. 182) . — Free except in Stratiomyiidae ; head in other families usually with 181 strong thorns, or if tliese are absent the antennae are very short and project downward and ontward and do not curve over the upper margin of the eye or reach nearly to l)ase of wing ; thoracic respiratory organs sessile, rarely stalk-like; legs of variable length ; abdomen usually armed with strong spines or bristles, or if unarmed there are only 4 or 5 distinct pairs of abdominal spira- cles BRACHYCERA (p. 307). IMAGINES Antenna consisting of at least 7 joints, frequently filiform, rarely conspicuously thickened, but if so the joints are distinct and the flagellum does not appear as a single joint with poorly defined subdivisions, and the palpi are pendulous, consisting of 4 or 5 joints; antennae with or without whorls of hair on the joints, never with a terminal arista or style; palpi always pendulous, normally consisting of 4 or 5 joints, very rarely of only 2 NEMATOCERA (p. 182). Antennae consisting of 3 joints, the third occasionally having more or less distinctly annulated subdivisions, but in such cases the palpi are porrect and consist of 1 or 2 joints ; antennae with short pubescence or with thick branches, in some families with either a terminal or subterminal style or arista; palpi projecting forward, consisting of 1 or 2 joints.' BRACHYCERA (p. 307). 182 Division NEMATOCERA TABULAR ARRANGEMENT OF FAMILIES My present grouping of the Nematocera is as follows. Tribes'^ Polyneura Supcrfcunilies Tipuloidea Families Tipulidae Limnobiidae Ptychopteridae Rhyphidae Eucephala Oligoneura Mycetophiloidea Culicoidea Chironomoidea Cecidomyioidea Bibionoidea Bolitophilidae Mycetophilidae Sciaridae Macroceridae Platytiridae Psychodidae ^ Blepharoceridae Culicidae Dixidae Ceratopogonidae Chironomidae Orphnephilidae Cecidomyiidae Bibionidae Scatopsidae Simuliidae The sequence of the families in the keys is not in accordance with the above list, the keys being framed to facilitate identification and not to indicate affinities. *Tribe in this paper does not have the application given to it in contemporary papers, but has that which Brauer gave it. He used it to designate his subdivisions of the larger divisions of Nematocera, etc. 183 Keys to Families LARVAE 1. Head incomplete; thorax and abdomen combined consisting of 13 segments; larvae peripneustic ; usually with a chitinized plate (very distinct in mature larvae) on ventral surface of second thoracic segment Cecidomyiidae (p. 293) . — Without the above combination of characters 2 2. Head and thoracic and first and second abdominal segments fused; larvae with minute abdominal spiracles; abdomen with a ventral longitudinal series of sucker-like discs Blepharoceridae (p. 274) . — Head free, or if retracted within or fused with prothoracic segment the other thoracic segments are distinct 3 3. Head complete, enclosing first ganglion ; mandibles opposed 5 — Head incomplete posteriorly, either with 3 deep wedge-shaped slits, 2 on dorsum and 1 on venter, or the ventral surface very poorly chitinized and the dorsal one posteriorly in the form of 4 slender heavily chitinized rods, with a weakly chitinized divided plate on anterior half of the dorsum 4 4. Apical abdominal segment with 6 radiating protuberances, which are rarely poorly developed but frequently unequally so; body segments with regularly placed bristles, as shown in Figure 1, Plate XXVIII ; head heavily chitinized, dorsally slightly arcuate and with 2 longitudinal slits, ventrally slightly rounded and with a central slit ; antennae longer than maxillary palpi ; labium pointed, not divided into 2 plates, the anterior margin dentate; mandibles very stout, with only 2 teeth (at apex) in species with- out apical processes Tipulidae (p. 191). — Apical abdominal segment with at most 5 radiating teeth, or if 6 are present the labium is subdivided centrally ; body usually with- out regularly placed bristles, frequently with dense surface pilosity; head sometimes weakly chitinized and without distinct labium ; antennae sometimes short and slender and not as long as maxillaiy lobe (not palpus) ; labium frequently subdivided into 2 plates; mandibles never with only 2 teeth. Limnobiidae (p. 207). 5. Thoracic segments fused and dilated, forming a complex mass .... Culicidae (p. 276) . — Thoracic segments not fused, distinct 6 6. Larvae peripneustic, or with at least rudimentary abdominal spiracles 7 — Larvae amphipneustie or metapneustic 12 7. Larvae with rudimentary abdominal spiracles ; mouth with a large articulated process on each side which bears a number of long hairs and closes, fan-like, when at rest; posterior abdominal seg- ments dilated, the last one armed on venter with a sucker-like disc which bears concentric series of bristles, by means of which the 184 larvae retain their hold upon rocks, etc., in the streams where they are found Simuliidae (p. 302) . — Larvae with distinct though sometimes small abdominal spiracles ; mouth without fan-like processes ; posterior abdominal segments not noticeably dilated, the last without sucker-like disc ; terrestrial species 8 8. Antennae elongate; body armed with conspicuous bristles or hairs 9 — Antennae usually short and inconspicuous, sometimes apparently absent ; body without conspicuous bristles 10 9. Anal spiracles at the apices of a pair of long stalk-like processes .... SCATOPSIDAE (p. 300) . — Anal spiracles not noticeably elevated, situated near base of dorsal surface of apical segment Bibionidae (p. 298). 10. Dorsal, or clypeal, sclcritc of head not conspicuously tapered pos- teriorly; antennae well developed Bolitophilidae (p. 247). — Dorsal, or clypeal, sclerite of head conspicuously tapered pos- teriorly; antennae almost indistinguishable 11 11. Lateral sclerites of head meeting on ventral line only for a short space immediately caudad of mouth-opening, not connected at posterior margin Mycetophilidae (p. 248) . — Lateral sclerites of head connected for a very short space behind mouth-opening and again near posterior margin SCIARIDAE (p. 258) 12. Dorsal surface of first and second abdominal segments each with 2 wart-like elevations somewhat resembling pseudopods, the apices of which are armed with numerous small hook-like setae; larvae aquatic, amphipneustic Dixidae (p. 279). — Dorsal surface of first and second abdominal segments without ele- vated processes 13 13. All or some of the dorsal segments with narrow, chitinized, strap- like transverse bands, or the apical segment in the form of a short chitinized tube ; rarely the ventral abdominal segments bear a central series of sucker-like discs Psychodidae (p. 264). — Dorsum without narrow, chitinized, strap-like bands, apical segment not in the form of a short chitinized tube ; ventral abdominal seg- ments never with sucker-like discs 14 14. Apical abdominal segment with long, slender respiratory tube .... Ptychopteridae (p. 238) . — Apical abdominal segment without long respiratory tube 15 15. Antennae undeveloped, appearing as pale round spots on sides of head ; ventral surface of head with the sclerites contiguous ante- riorly, widely separated posteriorly 16 — Antennae pedunculate, usually well developed; ventral surface of head with sclerite contiguous on entire length, not separated widely posteriorly 17 185 16. Head subquadi-ato ; abdominal sotynuMits with a nunibcu of I'ounded transverse ridges Pi^tyukidae (p. 260). — Head elongate ; abdominal segments without transverse ridges Mycetophiltdae (i). 248) . 17. Abdominal segments not subdivided 18 — Abdominal segments subdivided by means of transverse constric- tions 19 18. Larva very slender, tapering towards the extremities, without thoracic or anal pseudopods or surface hairs except about 8 at apex of abdomen, aquatic in habit; or stout, with well-defined segments which are armed with strong bristles, some of which are lanceolate; pseudopods present; terrestrial, living in manure or under bark, etc Ceratopogonidae (p. 281) . — Larva rarely very slender, generally of an almost uniform thickness, rarely with the thoracic segments appreciably swollen but not fused; abdominal and thoracic segments frequently with rather noticeable soft hairs, the last segment almost invariably with a conspicuous tuft of hairs on dorsum near apex ; pseudopods al- most always present, sometimes only the thoracic one distinguish- able in terrestrial f oi-ms-which are very rare Chironomidae (p. 284) . 19. Body slender, tapering; abdominal segments each with a single con- striction near anterior margin ; apical segment either with 5 short terminal processes or without distinct processes Rhyphidae (p. 241). — Body stout, of uniform diameter; abdominal segments each with 2 distinct constrictions ; apical segment with 4 rather long processes, the lower pair longer than the upper. .Limnobiidae, pt. (p. 207). PUPAE 1. Head with several strong thorns in a vertical series on the median line ; pupae enclosed within galls on various parts of plants .... Cecidomyiidae, pt. (p. 293) . — Head wdthout strong thorns, or if at base of each antenna there is a protuberance it is not sharp and thorn-like, and the pupae are not enclosed in galls on living plants 2 2. Pupa enclosed Mdthin a tough, parchment-like envelope consisting of the hardened larval skin, which resembles a muscid puparium. . ; Cecidomyiidae, pt. (p. 293) . — Pupa free, or if enclosed it is within a cocoon which is not parch- ment-like and does not resemble a muscid puparium 3 3. Thoracic respiratory organs sessile ; abdomen without strong thorns or leaf -like elevations ; legs straight 4 — Thoracic respiratory organs stalk-like, or if sessile the abdomen has strong thorns or leaf -like elevations, or the legs are recurved against base of abdomen and apex of thorax, or the coxae do not 186 conceal the sternopleura and the scape of the antennae is almost globose ; legs straight or recurved 8 4. Legs short, apices of hind tarsi projecting slightly beyond apices of wings ; antennae short, curved across middle of eye BiBIONIDAE (p. 298). — Legs elongate, usually all tarsi projecting for a considerable dis- tance beyond apices of wings ; antennae elongate, extending to or beyond bases of wings 5 5. Antennae almost straight, noticeably flattened, extending to bases of wings; thorax not much swollen in front, its anterior pro- file not declivitous Platyuridae (p. 260) . — Antennae distinctly curved, not ilattened, extending beyond bases of wings 6 6. Thorax conspicuously swollen, almost globose, its anterior profile de- clivitous; sternopleura concealed Mycetophilidae (p. 248). — Thorax not conspicuously swollen, the anterior profile not declivi- tous 7 7. Scape of antennae much swollen, globose ; abdominal spiracles small or absent ; sternopleura remarkably enlarged, not concealed by fore coxae and femora Chironomidae (p. 284). — Scape of antennae not much swollen ; al^dominal spiracles distinct ; sternopleura not visible, concealed by the large coxae and femora of the fore legs Cecidomyiidae, pt. (p. 293). SCIARIDAE, pt (p. 258). 8. Thoracic respiratory organs slender, long, and tube-like: legs straight, extending well beyond apices of wings; body without armature except a pair of hairs on anterior margin of head; sternopleura concealed Cecidomyiidae, pt. (p. 293). SCIARIDAE, pt (p. 258). — Species without tlio above combination of characters, abdomen usually with hairs or spines, or the sternopleura is exposed 9 9. Pupa in a pocket- or slipper-shaped cocoon consisting of coarse threads, from the wide, open extremity of which project the thoracic respiratory organs, each of the latter consisting of 4 to 60 tube-like branches on a common base; rarely the cocoon is a mass of rather loose threads Simuliidae (p. 302). — Pupa free, or if enclosed or partly so the cocoon is not pocket-like and the respiratory organs do not consist of tube-like branches. 10 10. Pupa when seen from above oval in outline, the abdomen at base not conspicuously narrower than thorax, so that the lateral outline is continuous ; dorsal surface with very strong, almost chitinized, membrane 11 — Pupa with the abdomen well differentiated from thorax, the dorsum membranous, or if strong and almost chitinized, then with surface spines 12 187 11. Thoracic respiratory organs lamelliform, consisting of 4 flat plates, the broad sides of which are contiguous Blepharoceridae (p. 274) . — Thoracic respiratory organs simple, tube-like PSYCHODIDAE, pt. (p. 264) . 12. Apical abdominal segment terminating in 2 or 4 paddle- or fin- shaped organs which are fringed on all or a part of their outer surfaces with strap-like hairs ; or if the apical segment terminates in 2 long subconical processes the tarsi are, as in the other group, recurved against the ventral surface of the base of abdomen and apex of thorax so that they do not extend beyond the apices of wings 13 — Apical abdominal segment obtuse, armed with short or elongate spines or thorns, or if ending in a pair of long, slender processes these are more or less oval or circular in transverse section and without strap-like hairs; tarsi generally entirely straight, rarely the apices of the hind pair incurved slightly, but they are never recurved as above 18 13. Thoracic respiratory organs terminating in numerous thread-like filaments Chironomidae, pt. (p. 284) . — Thoracic respiratory organs consisting of a single stem, in some cases with a few long, or many short, scale-like surface hairs, but never terminating in numerous thread-like filaments; or occa- sionally the thoracic respiratory organs are not elevated 14 14. Thoracic respiratory organs not elevated, sternopleura exposed .... Chironomidae, pt. (p. 284) . — Thoracic respiratory organs conspicuously elevated 15 15. Thoracic respiratory organs situated close to anterior margin of thorax ; thorax and abdomen without stellate hairs Chironomidae, pt. (p. 284) . — Thoracic respiratory organs situated close to middle of thoracic dor- sum -1" 16. Apical abdominal segment ending in 2 or 4 broad, flat, paddle-like plates CuLiciDAE, pt. (p. 276). — Apical abdominal segment ending in 2 long subconical processes . . 17 17. Apical processes armed at apices and on middle of their outer mar- gin with short hairs (3:1) Culicidae, pt. (p. 276). — Apical processes unarmed Dixidae (p. 279). 18. Apices of legs not extending beyond apices of wings .19 — Apices of posterior legs at least extending beyond apices of wings ^ 20 19. Apical abdominal segment ending in 2 conical processes Ceratopogonidae (p. 281 ) . — Apical abdominal segment ending in 2 upper and 2 lower short thorns Psychodidae, pt. (p. 264) . 188 20. Thoracic respiratory organs long, bifid; apical abdominal segment rounded, without processes; abdominal spiracles pedunculate. . . . SCATOPSIDAE (p. 300). — Thoracic respiratory organs simple ; apical abdominal segment not rounded, generall}^ armed with protuberances 21 21. Thoracic respiratory organs elevated but little above the level of disc of thorax ; tarsi of the fore legs overlapping those of mid pair, the latter overlapping those of hind pair, all rather closely fused together and to wings Rhyphidae (p. 241). — Thoracic respiratory organs very conspicuously elevated ; legs not as above 22 22. Thoracic respiratory organs equal in length, rarely with one twice as long as the other ; anterior, middle, and posterior tarsi distinct 23 — Thoracic respiratory organs of conspicuously unequal length, one many times as long as the other ; anterior tarsi overlapping mid- dle pair Ptychopteridae (p. 238). 23. Abdominal segments each with 1 transverse row, sometimes 2 such rows, of thorn-like protuberances ; palpi recurved at apices TiPULIDAE (p. 191). — Abdominal segments rarely with distinct thorn-like protuberances, usually with weak hairs ; palpi straight, not recurved at apices . . LiMNOBIIDAE (p. 207) . IMAGINES 1. Wing with at least 9 veins extending to the margin (exclusive of the anal vein) ; if there are only 8 such veins the radius is 3-branched, the second branch having its base proximad of the radio-medial cross-vein 2 — Wing with less than 9 veins extending to the margin, or the vena- tion not as above 8 2. Mesonotum with a more or less distinct V-shaped suture; male hypopygium generally very large, chitinous; female ovipositor conical, chitinized, and generally protruded 3 — Mesonotum without distinct suture, or if there is a poorly defined suture it is not V-shaped 5 3. Wing with 2 anal veins 4 — Wing with 1 anal vein Ptychopteridae (p. 238). 4. Last palpal joint slender, much longer than the combined lengths of the 3 preceding joints; auxiliary vein terminating in first vein. . . TiPULIDAE (p. 191) . — Last palpal joint at most but little longer than the combined lengths of the preceding joints; auxiliary vein usually terminating in costa, connected with first vein by a cross-vein LiMNOBIIDAE (p. 207). 5. Costa continued around the hind margin of the wing 6 — Costa discontinued at apex of wing Rhyphidae, pt. (p. 241). 189 6. Wing veins without eonspicuons scale-like hairs. .Dixidae (p. 279). — Wing veins with conspicuous scale-like hairs 7 7. Wings short and broad, ovate, occasionally pointed apically ; tibiae without apical spurs; small, robust species with rather short densely haired legs Psychodidae (p. 264). — Wings elongate, narrow ; tibiae with apical spurs ; rather large, slen- der species, Avith long, slender, usually moderately hairy or scaly legs CuLiciDAE (p. 276) . 8. Wing with 2 to 4 distinct longitudinal veins Cecidomyiidae (p. 293 ) . ■ — Wing with 5 or more longitudinal veins 9 9. Wings with a secondary reticulation of fine creases or lines in addi- tion to the veins; slender tipulid-like species with long slender legs Blepharoceridae (p. 274) . — Wings without a secondary reticulation of fine creases, at most with a longitudinal furcate crease between media and cubitus 10 10. Abdomen in both sexes with a conspicuous flap-like scale at base of dorsal surface which is detached posteriorly and fringed with long hairs Simuliidae (p. 302) . — Abdomen without such basal process 11 11. Second basal cell of wing present 12 — Second basal cell of wing absent .13 12. Antenna consisting of 2 stout joints, and an apical arista-like one composed of 9 or 10 segments Orphnephilidae (p. 290). — Antenna composed of 10-11 joints, the apical portion stout, not dif- ferentiated arista-like Bibionidae (p. 298). 13. Antenna consisting of 10-11 joints in both sexes (10 if scape is re- garded as consisting of 1 joint), the joints of central portion of flagellum shorter than broad ; radius and costa conspicuous, the other veins indistinct ; at least the mid and hind tibiae without apical spurs Scatopsidae (p. 300) . — Without the above combination of characters 14 14. Coxae unusually elongated 15 — Coxae not unusually elongated 19 15. Radius with 3 branches ; medio-cubital cross- vein present 16 — Radius with only 2 branches, or if there are three present the medio- cubital cross-vein is absent Mycetophilidae (p. 248). 16. Radio-medial cross-vein present, causing the base of the first poste- rior cell to be more or less broadly truncate .17 — Radio-medial cross- vein apparently absent, fused with base of third branch of radius so that the base of first posterior cell is acute . 18 17. Medio-cubital cross-vein much proximad of the radio-medial, caus- ing the posterior portion, divided longitudinally by media, to be much shorter than the anterior portion . .Bolitophilidae (p. 247) . — Medio-cubital cross-vein almost directly in vertical line with the radio-medial, the 2 cells divided longitudinally by media subequal in length Rhyphidae, pt. (p. 241) . 190 18. Antennae short, thick, and often flattened. . .Platyuridae (p. 260). — Antennae very long, usually exceeding in length that of body, very slender Macroceridae (p. 260). 19. Mouth parts chitinized, constructed for piercing, not in the form of a long slender process Ceratopogonidae (p. 281). — Mouth parts not chitinized, fleshy, sometimes in the form of a long slender process 20 20. Radius with 2 branches Sciaridae (p. 258). — Radius with 3-4 branches, if less or indistinct the antennal joints with very long plumes in the male and very conspicuous constric- tions between them in the female Chironomidae (p. 284). Tribe Polykeura I have included in this tribe, as I regard it, but one superfamily, Tipuloidea, containing the families Tipulidae, Limnobiidae, Ptychop- teridae, and Rhyphidae. Brauer limited his tribe Polyneura to Tipulidae (inclusive of Limnobiidae), placing the other two families in Eucephala. I have placed this tribe first in my arrangement because I consider the adults much more primitive structurally than the most generalized forms in the other groups. The larvae undoubtedly show more special- ization than do those of Mycetophiloidea both in the structure of the head, if we accept the capsule as the criterion, and in the respira- tory system, but I find that the larvae of many closely allied species in different families show quite striking distinctions even though the adults are almost inseparable, and therefore have decided to consider the tribe as more generalized than the others. The sequence of fami- lies does not show an unbroken line, but, rather, represents a series of divergent lines of varying lengths, no two of which start from a com- mon point. Superfamily Tipuloidea SUPERFAMILY CHARACTERS Larva. — Head incomplete posteriorly, wholly or partly retractile, or if the head is complete the abdomen has the anterior 6 segments sub- divided, or the posterior respiratory tube is much elongated and mem- branous, and distinct paired ventral pseudopods are present on anterior half of body. Head with opposed mandibles ; antennae well developed. Pupa. — Head without conspicuous armature except in some Limnobiidae ; antennae elongate, curved over upper margin of eyes. Wings and legs closely fused to thorax, the former very short, the latter never extending to apex of abdomen ; thoracic respiratory 191 organs usually elevated, one of them much longer than the other in Ptychopteridae, the two normally of equal length and usually slender in Tipulidae, ear-like, appearing like vertical plates, in some Limno- biidae, while in Rhyphidae they are but little elevated and rather stout. Abdomen in Rhyphidae and most Tipulidae circular in cross-section, usually with 2 transverse series of more or less leaf-like or thorn-like protuberances on each segment. Imago. — Distinguishable from all other Nematocera by the pres- ence of the discal cell of wing. Mycetobia has no discal cell. This genus has been placed by most writers in the Mycetophiloidea, but lately its affinities with Rhyphidae have been considered closer, and Edwards traces in the presence of a well-defined gular plate a distinct connection with that family, this plate being almost invariably absent in Mycetophilidae, and even when present differing materially from that of Mycetobia. The venation of the Mycetobia wing differs from that of Mycetophilidae in that the second branch of the radius has its base proximad of the radio-medial cross-vein instead of distad of it. The female of Mycetobia has chitinized spermathecae, this character separating it from Mycetophilioidea, no genus of which possesses them. Some Tipulidae have no discal cell, but they all have a distinct V-shaped suture on the dorsum of the thorax — a character which dis- tinguishes them from other Nematocera. Ptychopteridae possesses an incomplete V-shaped or slightly sinuous thoracic suture, and in com- mon with related Nematocera, except Rhyphidae, has very long legs, slender wings, and a long slender body. Allocation of species of the families must be arrived at by using the key to families of the Nematocera on a previous page. Family TIPUUDM This family as limited in the present paper contains only three subfamilies: Dolichopezinae, Ctenophorinae, and Tipulinae. Only the two last named are known to me in their immature stages. The number of species of Ctenophorinae in North America is small, but the genus Tipula, in Tipulinae, contains a very large number of species, the larvae, pupae, and imagines of which in very many cases bear a striking resemblance to each other. With the present collection it is not possible for me to do more than to indicate the principal characters useful in distinguishing the larvae and pupae from each other and from those of other families. 192 FAMILY CHARACTERS Larva. — Head heavily chitinized, retractile within prothorax; posterior portion deeply cleft longitudinally, one incision on each side of dorsum extending to, or almost to, middle, and one in center of venter extending beyond middle. Antennae elongate, consisting of an elevated base, an elongate joint — in Tipula at least four times, in Xiphnra not more than twice, as long as broad — and a very short apical process. Front and clypeus fused, the former with a distinct plate on each side, the anterior margin of which is armed with a few bristles and many hairs; labrum fringed with hairs anteriorly; epipharynx with a number of spines or short processes. Maxillae well developed, fringed on the inner and anterior margins with hairs, and sometimes spinose ; palpi small. Mandibles stout, the apex rounded and with 2 teeth more or less equal in size, lower margin with 2 or more teeth, inner upper margin with a fringe of hairs near middle. Labial plate (submentum) in the form of a flat plate, its outline medianly produced into an acute point anteriorly, the margin more or less dis- tinctly dentate. Hypopharynx heavily chitinized, in the form of a flat plate the anterior margin of which is usually dentate, and with a posterior inverted-U-shaped chitinized piece which arches over the oesophageal opening. Body cylindrical ; segments usually with dis- tinct hairs which are situated on certain portions of each segment, their arrangement being uniform throughout the family; pseudopods present or absent ; segments always with transverse linear depressions, most distinct on dorsum ; apical segment with 6 processes, rarely with- out these being well developed; ventral surface of apical segment in afjuatic and semiaquatic species with fringes of soft hairs on apical processes and with slender protrusive blood-gills ; terrestrial forms with the fringes of hairs much reduced or absent, and the slender protrusive blood-gills usuallv absent, their function being performed by an irregular protrusive membranous organ. Pupa. — The pupae differ from those of IJmnobiidae in minor characters only, the principal distinction between them and pupae of the genus Liuuwhia and several other genera consisting in the form of the thoracic respiratorv organs, those of Tipulidae, exclusive of Ctenophorinae, being long and slender, while those of the other family are stout and resemble a chitinized flattened plate. Many of the Limnobiidae, however, have slender thoracic respiratory organs, and otlier characters must be depended upon to distinguish them from Ti])uli(lae. A brief summarv of the characters of tipulid pupae is as f .IImws: head without projecting chitinized armature; antennae 193 never swollen at bases; thoracic respiratory organs slender, of mod- erate length, sometimes slightly swollen at apices — except in Cteno- phorinae, in which they are heavily chitinized, flattened, and highly glossy; legs exceeding the wings in length. Abdomen with i or 2 transverse series of short protnberances on each segment except basal and apical. Palpi recurved at apices. Imago. — See synopsis of families. HABITS OF LARVAE Most of the larvae are scavengers, feeding on decaying vegeta- tion, in mud containing vegetable debris, or' in rotten wood. Occa- sionally some species of Tipiila cause injury to crops such as oats and hay, or to pastures, by feeding upon the roots of the growing plants. Many of the species are aquatic or semiaquatic, living among floating vegetable matter along the margins of ponds or streams. The food consists of algae and various kinds of vegetable matter. HABITS OF IMAGINES The imagines occur commonly in damp situations, especially where there is a rank growth of vegetation. They feed upon nectar of flowers and upon moisture on vegetation and on the ground. Many of the species are readily attracted to lights. Keys to Subfamilies LARVAE 1. Mandibles with 2 teeth ; antennae about twiee as long as broad Ctenophorinae. — Mandibles with more than 3 teeth ; antennae about 4 times as long as broad Tipulinae. pupae 1. Thoracic respiratory organs broad, glossy, and heavily chitinized (PL XXXII, Fig. 20) Ctenophorinae. — Thoracic respiratory organs slender, opaque, not more heavily chitinized than dorsum of thorax Tipulinae, imagines 1. Legs very long and slender, the tarsi especially so ; anterior branch of second vein absent, indistinguishable, or perpendicular DOLICHOPEZINJiE. 194 — Legs long but not very slender; anterior branch of second vein present, oblique 2 2. Antennae of male pectinate or subpectinate Ctenophorinae. — Antennae not pectinate Tipulinae. Subfamily CTENOPHORINAE I have before me only a part of a larval exuvium — consisting of the head — and the pupal exuvium of one species of this subfamily, and am consequently unable to give a detailed description of the im- mature stages. The specimens, however, present characters that serve to distinguish at least this species from other Tipulidae known to me. As the characters of the species I have may not be in agree- ment with those of other genera in the subfamily, unknown to me, I shall restrict my generalizations to the genus to which it belongs. XiPHURA Brulle GENERIC CHARACTERS Larva. — Head large, heavily chitinized, arcuate on dorsum. Antennae short and stout, longer than maxillary palpi. Mandibles very stout, without teeth along the lower margin. Labial plate heav- ily chitinized, similar in general form to that of Tipiila. Maxillae well developed, the palpi short and stout. Hypopharynx similar in form to that of Tipula. Structure of body not known to me. The parts of the exuvium that remain show that there are numerous long 'surface hairs present as in Tipula, and the anal spiracles are large, sHghtly elevated, pale brown, with the central opening darker. Pupa. — Head without protuberances between antennae ; bases of antennae slightly swollen; labium rather prominently protruded. Thoracic respiratory organs heavily chitinized, glossy, irregularly and coarsely wrinkled ; apices of tarsi except those of the fore pair ex- tending much beyond apices of wings. Abdomen with a single en- circling series of short broad processes on each segment, the apices of which are acutely pointed. HABITS OE I^ARVAE All of the known larvae of this subfamily live in much-decayed trees, but whether thev feed upon the dead wood or some vegetable growth it contains, or upon insect larvae is unrecorded. 195 HABITS OF IMAGINES The imagines feed upon nectar and sap. They are usually rare, and normally occur in proximity to a suitable larval habitat. XiPHURA FUMiPDNNis Ostcu Sacken Ctenophora fumipennis Osten Sacken, Proc. Ent. Soc. Pliila., 1864, p. 47. Larva. — Head black, heavily chitinized, antenna short and stout, with a very short apical appendage (PI. XXXII, Fig. 2i) ; mandibles very robust, with 2 strong apical teeth (Fig. 25) ; labium dentate along its anterior margin, the central tooth simple; hypopharynx as in Figure 23, Plate XXXII, the anterior margin transverse. Pupa (PI. XXXII, Fig. 24). — Length, 22 mm. Dark brown, slightly shining. Thoracic respiratory organs glossy black. Abdom- inal spines dark castaneous at bases, becoming pale at apices. Head without protuberances, the organs in the same positions and of the same form as in Tipula; antenna extending beyond base of wing. Thoracic respiratory organs robust, about twice as long as their greatest width, heavily chitinized, their margins irregular (Fig. 20). Abdomen with strong leaf -like process at apices of segments, the tips of which are very acute ; lateral margin of segments with the same armature as in Tipula, one simple process before spiracles and another, bifid, behind them ; spiracles small but distinct ; apical segment elongated, its apical half consisting of 2 long upper, and 2 shorter lower, processes. The foregoing descriptions were made from the larval and pupal exuvia of a female specimen reared by Dr. H. Glasgow, June 8, 19 10. The larva was found in a much-decayed chestnut log in the Auger- ville woods, Urbana, 111. Subfamily TIPULINAE SUBFAMILY CHARACTERS Larva. — Head heavily chitinized ; antennae longer than maxil- lary palpi ; mandibles stout ; labium well developed, usually dentate ; hypopharynx large. Body without surface pilosity or with very short and dense pile; arrangement of bristles as shown in Figure i, Plate XXVIII. Apical segment with 6 finger-like processes, sometimes of very unequal length ; spiracles large. Pupa. — Head usually with 2 small membranous protuberances above bases of antennae ; antennae not swollen at base, and often with 196 a small thorn ; pal})! recurved at apices. Thorax with or without short wart-like protuberances on dorsum ; respiratory organs long and slen- der; halteres visible above upper margin of wing and resembling in certain respects the posterior wings in some lepidopterous pupae ; legs greatly exceeding length of wings. Abdomen with i, or 2, trans- verse series of thorns on ventral segments beyond apices of legs, the anterior series, if both are present, much weaker than the posterior; dorsal segments usually with a postmarginal series of thorns. HABITS OF LARVAD As far as known the larvae are scavengers, feeding upon decay- ing vegetable matter. Many species are aquatic or subaquatic. HABITS OF IMAGINES The imagines fly most readily in the late afternoou. The species I have observed in nature are flower frequenters. TiPULA Linne and Pachyrrhina Macquart As very few of the species before me have been reared, and are represented only by larvae or pupae or, at most, by both, there is at present no possibility of specifically identifying these immature stages. Neither is it possible for me to cite characters for the separation of the larvae of Tipida and Pachyrrhina, the reared material at hand being quite insufficient to justify any attempt at a generalization. I give a svnopsis of the characters that appear to me to be of primary importance in the separation of the forms I have studied, but, tm- fortunately, T can specifically identify only a very few of them, and as in my opinion detailed descriptions would occupy more space than their possible scientific value will warrant me in taking, only the notes and synopsis are presented. I leave this subfamily in this condition, however, with the hope that the work now being done by C. P. Alex- ander on the biology of the crane-flies will satisfactorily fill the very large gap in our knowledge of the early stages of the group. A complete study of our material is not at present contemplated, the forms described in this paper being included merelv as indices to the range of specific distinctions, and as adjuncts to the synoptic char- acters cited in the key to the families. Keys to Species LARVAE 1. Apical al)doniinal ventral sofjment with slender protrusive blood- gills 2 197 — Apical abdoiuiual voiilral se:;ni('iit with hlood-^ills in llic form of an irrcf^iilar j)rotuberan('e, rarely acute laterally 9 2. Ventral blood-gills not cons{)icuously longer than the stellate proc- esses on margin of stigniatal field, these processes slender, regu- larly and very conspicuously fringed Tipula sp. 1. — Ventral blood-gills conspicuously longer than stellate i)i'occsses, or the latter not regularly and conspicuously fringed, or the proc- esses very unequal in length 3 3. Stellate processes subequal in length, very short, their margins with regular fringe of short hairs 5 — Stellate processes very unequal in length, the ui)per two short, the lateral and lower ones much longer and with isolated groups of long hairs 4 4. Very large species, more than 40 mm. in length ; penultimate abdom- inal segment with a lateral process Tipula sp. 2. — Small species, 20 mm. in length ; penultimate abdominal segment without a lateral process Tipula sp. 2a. 5. Small species, not more than 30 nun. in length 6 — Larger species, more than 40 mm. in length 7 6. Body with dense pubescence which is most conspicuous on 2 narrow longitudinal lines on dorsum, giving the species the appearance of being vittate ; posterior latero-ventral bristles surrounded with stiff upright hairs Tipula eluta. — Body without dense pubescent vittae; posterior latero-ventral bristles not surrounded with stiff upright hairs . Tipula cunctans. 7. Body almost regularly cylindrical, as in eluta; posterior latero-ven- tral bristles not on pseudopod-like elevations, their bases sur- rounded with short, stiff, upright hairs; dorsum not conspicuously vittate Tipula sp. 4. — Body not regularly cylindrical, the segmentation deep, and the pos- terior segments with distinct pseudopod-like elevations ; poste- rior latero-ventral bristles situated on elevations and not sur- rounded with stiff upright hairs ; dorsum conspicuously vittate 8 8. The pale dorsal vittae composed of a number of closely placed pale dots ; dorsum with many small pale paired spots ; hairs not in- serted in dark brown dots Tipula ahdominalis. — The pale dorsal vittae linear ; dorsum with a number of very incon- spicuous pale dots ; hairs inserted in dark brown dots. Tipula sp. 3. 9. Apical abdominal segment with a conical protuberance on each side proximad of the processes on the margin of stigmatal field (PI. XXXI, Figs. 6, 7) Tipula sp. 6. - — Apical abdominal segment without a protuberance on sides 10 10. Upper 4 processes on anal segment deeurved, long, and pointed, much longer than lower pair, ventral respiratory organs acute laterally (PI. XXXII, Figs. 7, 8) ; prothorax with 2 horny protuberances on its dorsal margin anteriorly Tipula sp. 5. 198 — Upper 4 processes on anal segment not decurved, usually straight; ventral respiratory organ not acute laterally ; prothorax without horny protuberances on its dorsal margin anteriorly 11 11. Upper median pair of processes on apical abdominal segment very acutely pointed, their posterior face glossy brown, lower pair very small and widely separated ; hypopharynx with upper plate more acute than usual (PI. XXXI, Fig. 14) Tipula sp. 7. — Upper median pair of processes on apical abdominal segment not acutely pointed, lower pair of moderate size and rather close to- gether 12 12. Upper i)late of liypopharynx with acute teeth, its anterior outline distinctly convex (PI. XXXII, Fig. 13) Tipula hicornis. — Upper plate of hypopharynx with rounded teeth, its anterior out- line almost transverse (PI. XXXII, Fig. 15) PacJiyrrJiina ferruginea. PUPAE 1. Thoracic respiratory organs very long and slender, one much longer than the other, the longest one at least half as long as entire body Tipula sp. 1. ■ — Thoracic respiratory organs equal in length, not more than one fourth as long as entire body 2 2. Ventral abdominal segments beyond apices of tarsi with a median and apical transverse series of spines 3 — Ventral abdominal segments with only the apical series of spines. 4 3. Antennae with a distinct but short thorn on outer side at base ; f rons slightly furcate and covered with irregular small wart-like pro- tuberances between bases of antennae Tipula cimctans. — Antennae without thorn at base ; f rons not as above . . . Tipula eluta. 4. No minute thorns or bristles laterad of the 2 strong thorns on third and fourth ventral abdominal segments; protuberance between base of antennae and base of thoracic respiratory organs small, forming a distinctly isolated wart-like prominence Tipula trivittata. — One or two closely paired small thorns or 2 slender bristles laterad of the 2 strong thorns on third and fourth ventral abdominal seg- ments; space between base of antennae and base of respiratory organs filled with a regularly rounded prominence 5 5. Thoracic respiratory organs short, not extending more than half- way from their bases to medio-dorsal protuberances ; 2 weak bris- tles laterad of the ventral series of thorns on abdominal segments ; apical segment of female much elongated (PI. XXVIII, Fig. 8) Tipula serta? — Thoracic respiratory organs long, extending almost or quite to medio-dorsal protuberances; one or two small thorns laterad of 199 the series of thorns on ventral abdominal segments; apical seg- ment of female not elongate 6 6. Apical abdominal segment drawn out into a long process consisting of an up])cr and a lower pair of tube-like organs (PI. XXXTI, Fig. 18) Tipiila sp. 7. — Apical abdominal segment short and stout, not drawn out into a long process 7 7. Apical segment with 4 small but distinct lobes at tip (PI. XXVIII, Fig. 6) PachyrrMna ferruginea. — Apical segment with 2 rather large lobes at tip (PI. XXVIII, Fig. 7 ) Tipula hicornis. TiPULA sp. I Larva. — Length, 20-22 mm. Dark brown, with an indistinct pale central vitta and slightly paler along sides. Antennae about 4 times as long as their basal width, dis- tinctly tapering apically; apical joint very small; frontal plate with a rather conspicuous tuft of hairs near outer anterior angle; labrum not conspicuously hairy; mandibles as in Figure 2, Plate XXXII; hypopharynx more elongate than in other species examined, its an- terior margin with 3 rather large teeth in an almost transverse series and a much smaller one at angles (PI. XXXII, Fig. i); labium as in Figure 3, Plate XXXII. Body without surface pilosity ; bristles very weak though long; latero-ventral bristle on posterior portion of each segment usually duplicated, sometimes triplicated; outer bristle of the transverse series on posterior portion of each of the dorsal segments duplicated ; lateral bristles weaker than the dorsal and ven- tral series; apical segment as in Figure 8, Plate XXXI. Pupa (PI. XXVIII, Fig. 14).— Length of body, 15 mm.: that of longest respiratory organ, 9 mm. Dark brown, the lateral longi- tudinal elevation along the spiracular region pale ; abdomen with dor- sum indistinctly, and venter distinctly, bivittate. Thoracic respiratory organs very slender, unequal in length, their apices flattened and split longitudinally; apices of fore tarsi falling short of apex of first abdominal segment beyond apices of wings, mid tarsi extending slightly beyond the apex of that segment, hind tarsi extending to middle of next segment. Exposed ventral abdominal segments, except apical, each with 2 series of thorns on posterior division, the anterior consisting of 2, widely separated, and the posterior of 4 to 14; no thorns on area covered by legs, and the next 2 series slightly interrupted at middle ; apical segment with 4 long up- 200 wardly curved spine-like processes which are armed at apices with several short thorns. The foregoing descriptions are made from a larva and pupa bearing the Laboratory accession number 26281, obtained by Dr. S. A. Forbes in Delavan Lake, Wis., May 25, 1892, taken in an inlet among vveeds at the surface, and one larva, accession number 26282, taken by the same collector at the same place May 26, 1892. The species is undoubtedly truly aquatic, judging from the struc- ture of the apical segment. No means is at hand for associating the early stages with any described imago. TiPULA sp. 2 Larva (PI. XXVIII, Fig. 2).— Length, 45-55 mm. Brown, without well-defined vittae (alcoholic specimens). General structure as in above-cited figure. The principal differ- ences in head structure between this species and the preceding lie in the shape of the labium and the hypopharynx, the former (PI. XXXII, Fig. 5) having a strongly produced central tooth and no distinct laterals, while the latter (PI. XXXI, Fig. 13) has the anterior margin with only 2 weak protuberances and no rounded teeth; frontal plate as in Figure 9, Plate XXXI. Body without close pubescence, the armature as shown in Figure 2, Plate XXVIII ; abdominal segments with the posterior lateral bristles on both dorsum and venter situated on pseudopod-like elevations; apical segment as in Figure 3, Plate XXVIIL The foregoing description was made from alcoholic specimens in the Laboratory collection bearing the following data: Accession number 25756, Urbana, May 7, 1888, taken in woods (C. A. Hart) ; and two examples submitted by J. A. Hyslop (ace. 6687) from Hagerstown, Md. TiPULA sp. 2a This specimen may really be a young example of the foregoing, as it differs only in size (20 mm.) and in having a process on each side of the penultimate abdominal segment. Locality, Blacktail Deer Creek, Yellowstone National Park, August 28, 1890; taken in an aquatic collection among vegetable debris (S. A. Forbes). TiPULA ABDOMINALIS Say Ctenophora atdominalis Say, Jour. Acad. Nat. Sci. Phila., Vol. 3, p. 18. (1823) Tipula ahdominalis Say, Needham, Bull. 47, N. Y. State Mus., p. 575. (1901) 201 A larva which was assumed to be of this species was described by Needham, as cited above. The markings given in that description appear to justify me in considering the species following as distinct from abdominalis. TiPULA sp. 3 Larva. — Length when full-grown, 50 mm. Dark greenish brown, with :S continuous moderately broad longitudinal vittae on dorsum, a dark brown median vitta, and a number of isolated pale dots; surface hairs set in small blackish or dark brown dots. Head rather small in comparison with size of larva, lateral view as in Figure 4. Plate XXXII ; antennae normal in size ; labial plate (PI. XXXII, Fig. 6) with one very large central tooth, with more or less distinct shoulders, and 3 smaller lateral teeth; hypopharynx (PI. XXXI, Fig. 12) with anterior margin of upper plate slightly convex, the central tooth of the five the largest. Body similar in general structure to that of Species 2, but the apical segment very different, quite closely resembling that of Species 4 except that the ventral blood-gills are distinctly shorter and stouter. Described from specimens obtained by Dr. S. A. Forbes in Black- tail Deer Creek, August 28, 1890, and in Slough Creek August 30, 1 89 1 — both in Yellowstone National Park. TiPULA sp. 4 Larva. — Agrees in general appearance and armature of the abdominal segments with eluta, but differs in being much larger (50 mm.) and in having the apical abdominal radiating processes much less acute (PI. XXXI, Fig. 5). The head agrees closely with that of Species 3, the labium (PI. XXXII, Fig. 9) and hypopharynx (PI. XXXI, Fig. 15) being of the same general structure, dififering only in having the former narrower and more acute anteriorly ; f ronto- clypeal region as in Figure 4, Plate XXXI ; mandibles as in Figure 26, Plate XXXII. Specimens are in our collection from Ithaca, N. Y. (March 21, 1897). TiPULA Sp. 5 Larva (PI. XXIX, Fig. 3). — Length, 27 mm. Separable from other species that do not have the long slender blood-gills on apical abdominal segment by a pair of slight elevations or tubercles on the dorsum of the anterior third of the prothoracic segment, and by the peculiar formation of the apical segment, shown in Figures 7 and 8, 202 Plate XXXII. The hypopharynx and labium agree with those of Pachyrrhina ferruginea. I have before me the specimen from which Mr. Hart drew up his description of his Species (6) in the paper on the "Entomology of the Illinois River and Adjacent Waters"*, and a number of speci- mens sent in by a farmer October 7, 1915, from an alfalfa field at Towanda, 111. TiPULA sp. 6 This is the Species (a) described by C. A. Hart in his paper on Illinois River species. The apical segment differs from that of any allied species known to me, and this character alone should enable one to identify it. As Hart did not figure this species I have pre- pared drawings of the apical segment which are presented herewith (PI. XXXI, Figs. 6,7). In addition to the specimen previously recorded from Havana, 111., I have before me one taken in a sandy swamp at Grand Crossing, 111., Nov. 7, 1891 (C. A. Hart). TiPULA sp. 7 Larva. — Length, 25—30 mm. Brown, apical segment yellowish white on the posterior surface, the 4 upper radiating processes con- spicuously blackened posteriorly, or on what is their inner or under surface when incurved, the lower pair with a black spot near apex which, because of the processes being normally curved upward, as in Figure I, Plate XXXI, is not usually visible. Head of normal size and shape, the dorsal and ventral surfaces as shown in Figures 2 and 3, Plate XXXI ; hypopharynx as in Figures 11 and 14 of the same plate; mandibles as in Figure 27, Plate XXXII. Body with weak pilosity, the arrangement of bristles and the general structure as in Pachyrrhina ferruginea; apical segment differing as stated in key. Pupa. — Length, 28-30 mm. Brown, slightly shining. Base of antennae with a sharp thorn-like process on anterior side ; a small rounded tubercle above and behind base of antennae. Thoracic respiratory organ about 10 times as long as its greatest width; post- spiracular and medio-dorsal thoracic protuberances large, the latter sharp and not bifiid, posterior protuberance small ; legs ending just before apex of third abdominal segment, the apices of fore tarsi fall- •Biill. 111. state Lab. Nat. Hist, Vol. 4, Art. VI, p. 217. 203 ing short of apices of mid pair. Two thorns on each side of third segment in line with apices of tarsi ; 6 thorns on other segments, the lateral one of each series weakest; apical segment as in Figure i8, Plate XXXII. This is the species described by C. A. Hart as Species (e) in the paper previously referred to. It occurs in humid earth and especially under logs or leaves. In addition to Hart's material I have before me two specimens from St. Clair Co., 111. (Nov. 26, 1886). TiPULA Ei/UTA Loew Tipula eluta Loew, Bull. Ent. Zeitschr., 1863, p. 290. The external characters of this species have been very fully de- scribed by C. A. Hart in his paper on the "Entomology of the Illinois River and Adjacent Waters"*. The details given here are merely supplementary. Larva (PI. XXIX, Fig. i). — Antennae about 4 times as long as basal width, slightly tapering apically; maxillary palpi longer than broad; labial plate with a large rounded central tooth, and 2 much smaller lateral teeth and 2 poorly developed protuberances on each side; hypopharynx similar to that of Species 4 (PI. XXXI, Fig. 15). Lateral abdominal bristles as shown in Figure i, Plate XXVIII. Pupa (PI. XXIX, Fig. 2). — Thorax with the postspiracular, medio-dorsal, and postero-dorsal protuberances small but distinct. Legs in female extending to apex of first abdominal segment beyond apices of wings, in male to middle of the next segment. Armature of ventral abdominal segments similar to that of Species i except that the second visible segment has the widely separated anterior pair of thorns reduced to mere hairs, and the other segments have these same thorns simple, with a small hair at base instead of 2 thorns as in that species; apical segment of sexes as in Figures 11, and 13, Plate XXVIII. These descriptions and the figures are made from specimens used by Mr. Hart as a basis for his descriptions of eliita in the paper above referred to. The specimens were obtained from the Illinois River at and near Havana, 111. The larva is usually found burrow- ing in the sand on the shore, but occasionally is found in the water. I have taken the larvae from wet mud and sand along the margin of a small stream at Muncie, 111., and very probably the species occurs in similar situations throughout the state. *Bull. 111. State Lab. Nat. Hist., Vol. 4, Art VI, pp. 212-214. (1895) 204 TiPULA CUNCTANS Say Tipula cunctaris Say, Jour. Acad. Nat. Sci. Phila., Vol. 3, p. 23. (1823) Larva. — Similar to the previous species in general appearance and structure, the principal distinctions being as follows : the f ronto- clypeal region is less hairy, the plates on either side having only an isolated tuft of hairs at outer anterior angle and one bristle and a short thorn on inner anterior protuberant area; the labial plate (PI. XXXII, Fig. lo) has 3 large teeth on each side of the central one; anterior outline of hypopharynx as in Figure 11 of same plate; the body is not densely pubescent, and shows no vittae on dorsum; and the short, stiff, upright hairs that surround the bristles in eluta are wanting. Pupa. — Length, 18-22 mm. Reddish brown, lateral margins yellowish. Slenderer than cluta. Head rather distinctly protuberant be- tween antennae, the surface with coarse rugae and a few small warts ; bases of antennae with a small sharp process on anterior surface. Area between base of antennae and respiratory organs regularly rounded; dorsum of thorax without the distinct protuberances so noticeable in cluta ; apices of fore, mid, and hind tarsi not in a transverse line, but each successively farther beyond apices of wings. All of the exposed abdominal segments with 2 series of spines each, the anterior one con- sisting of 2, widely separated, and the posterior series of 4-12, close- ly placed; the third and fourth segments have the anterior pair of spines reduced to mere hairs; dorsal segments with only the posterior armature distinct; apical segment of female as in Figure 19, Plate XXXII, that of male as in Figure 22. Described from examples in the collection obtained at Newton and Hillsboro, 111., April 1896. The species is very common through- out the state and, like 7\ hicornis, is sometimes destructive in meadows, pastures, and other grass lands, the larvae feeding on the roots of the plants. This species is usually found in quite different surroundings from those of eluta, being essentially terrestrial in habit and often found in fields which are rather dry and well removed from any body of water. Tipula trivittata Say Tipula trivittata Say, Jour. Acad. Nat. Sci. Phila., Vol. 3, p. 26. (1823) Pupa. — Length, 22-25 "i^n. Dark brown, lateral line pale. Bases of antennae with a sharp protuberance on anterior side; a 205 small but distinct elevated tubercle immediately behind antennal base. The usual 6 small elevations on dorsum of thorax, the medio-dorsal pair duplicated transversely; wings extending to apex of second ab- dominal segment; legs extending beyond apex of third, terminating in a straight transverse line. All dorsal segments except apical one with a transverse series of thorns on or near posterior margin, the series becoming successively stronger from basal segment to apical ; post- notum with 4 very small protuberances ; third and fourth ventral abdominal segments each with 2 widely separated thorns, fifth to eighth inclusive with 4 each; prespiracular and postspiracular spines of equal strength, both simple ; apical segments of male and female as in Figures 16, and 17, Plate XXXII. The foregoing description was made from exuvia supplied by Dr. E. P. Felt and J. A. Hyslop, the former obtaining his specimens at Albany, N. Y., May 5, 1909, and the latter obtaining his at Wolf- ville, Md., May 21, 1915. The species is represented in the Labora- tory collections by two imagines from Algonquin, 111. TiPULA sERTA*Loew? Tipula serta Loew, Berl. Ent. Zeitschr., 1863, p. 283. Pupa. — Length, 30 mm. Yellowish brown. Robust. Head with a pair of small rounded elevations above and between bases of an- tennae; antennae without a distinct basal process. Thoracic respira- tory organs less than 6 times as long as their greatest width ; post- spiracular protuberances in the form of rounded elevations ; medio- dorsal pair carinated, simple ; tarsi terminating in a straight trans- verse line at apex of third abdominal segment. Armature of ventral abdominal segments confined to posterior margins, that of third and fourth segments consisting of 2 thorns, that of remaining segments of 4; laterad of the thorns on each segment are 2 slender bristles; apical segment much elongated (PI. XXVIII, Fig. 8). The foregoing description was made from the pupal exuvium of a female that was reared from a larva found by the writer under a log at White Heath, 111., in March, 191 6 (Ace. No. 46302). Owing to the great uncertainty in identifying species of this ge- nus from descriptions, the above name should be regarded as a tenta- tive one. TiPULA BicoRNis Forbes Tipula bicornis Forbes, 16th Eep. State Ent. 111., p. 78. (1888) This species was originally described by Dr. Forbes, as above 20(j cited, the description of the imago being given on page 80. The species stands in the Loew collection at Cambridge, Mass., under the name bicornis Loew, but never was described by Loew. Mr. Hart, in his "Entomology of the Illinois River and Ad- jacent Waters" unfortunately entered in his key the larva of ainctans as that of bicornis. The larva of bicornis is almost inseparable by superficial charac- ters from that of Pachyrrhina fcrriiginea, but possibly with better and more material than I have, such separation may be feasible. In examples which I have dissected I find that the labial plate and hypopharynx furnish characters that appear to be of specific value. These differences are shown in Figures 12 and 13, and 14 and 15, Plate XXXII. The pupae of the two species are also very similar in structure, and I find in the shape of the apical segment of the females the only appreciable distinction. This difference is illustrated by Figures 5 and 7, Plate XXVIII. The apical segment of the male pupa may pro- vide characters for the separation of this sex also; I have no male pupa of bicornis for examinatfon. The species is very widely distributed in this state, and is some- times destructive to pastures, the larvae feeding on the roots of the grasses. Pachyrrhina ferruginea Fabricius Tipula ferruginea rabricius, Sept. Antl., Species 28. (1805) The larva (PI. XXVIII, Fig. 4) of this species bears a striking resemblance to 7\ bicornis and is found in the same situations. I have no well-preserved specimens of authenticated bicornis for com- parison of the external characters with those of ferruginea. The frontal plate is as in Figure 10, Plate XXXI, and dissection of the head shows the distinctions mentioned under bicornis (see PI. XXXII, Figs. 14, 15). Apical abdominal segment as in Figure 3, Plate XXX. The pupa is also very similar to that of bicornis, the only charac- ters that appear to be useful in their separation being found in the apical abdominal segment-as stated in key. (See PI. XXVIII. Figs. 5, 10, 12.) The species is common and widely distributed in Illinois. Principal Papers on North American Tipulidae Hart, C. A. '95. On the entomologv of the Illinois River and adjacent waters. Bull. 111. State Lab.' Nat. Hist., Vol. 4, Art. VI. 207 Needham, J. G. '07. Report of the entomologic field station conducted at Old Forge, N. Y., in the summer of 1905. Bull. N. Y. State Mus., No. 124 : 199-248. Needham, J. G., and Betten, C, '01. Aquatic insects in the Adirondaeks. Bull. 47, N. Y. State Mus. Osten Sacken, C. R. '69. The North American Tipulidae. Monographs of North Ameri- can Diptera, Part 4. (A list of additions and corrections appears at end of Part 3, which was published after Part 4.) Family LIMNOBIIDAB This family is of much greater extent than Tipulidae and contains a much larger number of genera, none of which in their larval and pupal stages — judging from the data at hand — show the same uni- formity that is found in the genera Tipula and Pachyrrhina. It is difficult to separate the larvae and pupae of the two families, but I believe that the following summary of characters will serve this pur- pose. PAMIL,Y CHARACTERS Z,arz/a.^Head in all subfamilies but Trichocerinae, Hexatominae, and Eriopterinae very similar to that of Tipulidae except that the antennae are much more slender, and frequently they are shorter than the maxillary palpi. The labial plate is often divided longitudinally in the center, each part being furnished with distinct teeth, while in all Tipulidae known to me the labial plate is entire and subtriangular, with a single apical tooth and usually several laterals. In Hexatominae and some Eriopterinae that I have examined the labium is not chitin- ized, and posteriorly the head is composed of 4 or 6 slender chitinized rods connected by weakly chitinized membrane. In Trichocerinae the head is complete, and the prothoracic spiracles are present. The mandibles in the species with tipulid-like head are much more slender than in Tipulidae, and in the latter when the apical segment has no protuberances the mandibles are very stout and have but 2 teeth, both at apex. The apical segment in Limnobiidae is very differently con- structed in the different genera, but as far as I have seen there are never 6 processes, which in Tipulidae is the almost invariable number. Pupa. — The pupae of all genera of this family known to me may be readily separated from those of Tipulidae by the straight palpi, since those organs in Tipulidae have their apices recurved. 208 HABITS OF LARVAE The larvae have more diversified food-habits and habitats than do those of Tipulidae. A summary of these is given under the dififer- ent genera dealt with in the text. HABITS OF IMAGINES The food of the imagines, when any is taken, usually consists of nectar. Keys to Subfamilies LARVAE 1. Thorax and abdomen with numerous long fleshy appendages Cylindrotominae (p. 210) . — Thorax and abdomen without long fleshy appendages 2 2. Labium not ehitinized ; mandibles long and siekle-shaped, toothed only on basal half; maxillae with a very long membranous lobe at anterior lateral angle ; apical segment with 4 processes, which are fringed with long hairs ; penultimate segment in preserved larvae much distended Hexatominae ^p. 232). — Labium heavily ehitinized except in Eriopterinae; mandibles stout, toothed on apical half ; and otherwise not as above 3 3. Apical abdominal segment terminating in a pair of long tail-like ap- pendages, the spiracles at their bases, above; labial plate divided in center Pediciinae (p. 216). — Apical abdominal segment terminating in 4 or 5 short protuber- ances, or at least not with 2 long terminal appendages 4 4. Apical abdominal segment with 5 short terminal protuberances, the central one on upper margin about as large as the others; body usually pubescent or roughened ; head posteriorly consisting of 6 slender rods Eriopterinae (p. 227). — Apical abdominal segment with 4 terminal protuberances or with- out any, or if thei-e are 5 the central one on upper margin is much smaller than the others and the head is not as above 5 5. Head complete ; prothoracic spiracles present Trichocerinae (p. 234). — Head incomplete posteriorly ; prothoracic spiracles absent 6 6. Body green, with dense groups of fuscous hairs on dorsum of seg- ments, which give it the a])pearance of being marked with black Limnobiinae, pt. (p. 212). ■ — Body yellowish, whitish, or brownish, without distinct groups of hairs as above 7 7. Segments broader than long, lateral margins of prothorax with 1 strong hair, those of the other segments with 2 such hairs Rhamphidiinae (p. 226). 209 — Segments at least as long as broad, lateral margins without strong hairs 8 8. Body covered with short decumbent hairs, or, if bare, without nar- row stripe-like locomotor areas; apical segment with 4 or 5 processes Limnophilinae (p. 220). — Body without decumbent hairs ; locomotor organs consisting of nar- row transverse strips on dorsum and venter which are slightly leathery and armed with short spinules LiMNOBIINAE, pt. (p. 212) . PUPAE 1. Thoracic respiratory organs very short and stout, not more than twice as long as their greatest breadth; armature of abdominal segments weak, the same on dorsum and venter, consisting of a single narroAv, chitinized or setigerous, band 2 — Thoracic respiratory organs very much elongated, usually more than 6 times as long as their greatest breadth or they are knobbed at apices; or abdominal armature usually strong, thorn-like or spinose, or not in the form of bands 3 2. Thoracic respiratory organs well separated basally LiMNOBIINAE, (p. 212) . — Thoracic respiratory organs subcontiguous basally Rhamphidiinae (p. 226). 3. A pair of large leaf-like projections above bases of antennae Hexatominae (p. 232). — No leaf-like projections above bases of antennae 4 4. Abdominal segments each with 2 or more very long thorn-like pro- jections on posterior margin, which are in some species armed with small branches; rarely these projections are confined to apical 2 segments Cylindrotominae (p. 210) . — Abdominal segments each with small spines, or if rather large pro- jections are present they are short and leaf-like, rather numerous, and unbranched 5 5. Thoracic respiratory organs stout, knobbed at apices Pediciinae (p. 216). — Thoracic respiratory organs slender, not knobbed at apices 6 6. Thoracic respiratory organs not slender and tube-like, flattened and but little elevated Eriopterinae, pt. (p. 227). — Thoracic respiratory organs long and usually tube-like, much ele- vated ' 7. Abdomen without dorsal or ventral armature ; thoracic respiratory organs not longer than width of thorax, slender and tube-like Eriopterinae, pt. (p. 227) . — Abdomen either with distinct armature on apices of dorsal segments or on both dorsal and ventral ones and with the thoracic respira- 210 tory organs longer than width of thorax ; or if the armature of ab- domen is very weak the thoracic respiratory organs are not tube- like but acute apieally Limnophiunae* (p. 220). IMAGINES 1. Only one submarginal wing-cell present 2 — Two submarginal wing-cells present 4 2. Antennae with 14 segments Limnobiinae. — Antennae Avith 16 segments 3 3. Tibial spurs present Cylindrotominae. — Tibial spurs absent Rhamphidiinae 4. Tibial spurs absent Eriopterinae. — Tibial spurs present 5 5. Subcostal cross-vein proximad of base of second vein . . . Pediciinae. — Subcostal cross- vein distad of base of second vein 6 6. Antennae with 16 or more segments 7 — Antennae with at most 10 segments Hexatominae. 7. Seventh vein short, abruptly deflected towards anal angle Trichocerinae. — Seventh vein normal, not deflected towards anal angle LiMNOPHILINAE Subfamily CYLINDROTOMINAE This subfamily includes but four genera, each containing from one to four or five species, and because of the peculiar anatomical characters of the diiferent stages it may yet be considered as entitled to separate family rank. I have treated the subfamily in this paper as belonging to Limnobiidae. SUBFAMIIvY CHARACTERS Z^arva. — Head similar to that of Tipulidae, the dorsal surface arcuate, heavily chitinized, and with 2 slits which usually extend proxi- mad of the middle. Antennae slender, longer than maxillary palpi. Mandibles stout, with a strong apical tooth, and several smaller teeth along the lower margin. Labial plate similar to that of Tipulidae, the central tooth simple or bifid. Thoracic and abdominal segments with long fleshy spine-like processes which may be either simple or more or less furcate. Apical segment wath 4 slender processes; spiracles rather small. Piipa. — Head without projections; antennae curved over eyes. Thorax very short; respiratory organs long and slender; wings ex- *I do not know what characters may serve to separate pupae of Limnophilinae and Trichocerinae. 211 tending to apex of second abdominal segment; legs, to or nearly to apex of third. Abdominal segments more or less distinctly sub- divided by transverse incisions; dorsum of all segments or of the apical 2 with long thorn-like processes ; lateral margins with short thorn-like protuberances. Imago. — See key to subfamilies. HABITS OF LARVAE The larvae of this subfamily feed upon living plants, and are, as far as I know, the only species of Tipuloidea that have this food-habit. They also differ from all other Tipuloidea except Dicranomyia in being green. It is very difficult to detect them upon their food plants, which consist of living mosses, or, in the case of Cylindrotoma, of Viola, Stellaria, and Anemone. Phalacrocera feeds upon sub- merged aquatic mosses. The larvae are very sluggish. HABITS OP IMAGINES The flies are rather sluggish, and may be swept from plants on which the larvae have fed or from those along the margins of streams or ponds. Keys to Genera LARVAE 1. Thoracic and abdominal processes long and slender, the posterior submedian pair on each abdominal segment furcate near bases; aquatic or semiaquatic species (PI. XXXIII, Fig. 1) Phalacrocera. — Thoracic and abdominal processes short and leaf-like, not furcate near bases, at most with short protuberances 2 2. Dorsal processes simple Cylindrotoma. — Dorsal processes with short protuberances anteriorly 3 3. Some of the dorsal processes with 4 short protuberances on their anterior surface Triogma. — None of the dorsal processes with more than 2 protuberances on their anterior surface Liogma. PUPAE 1. Only the apical 2 abdominal segments with long, rather slender protuberances (PI. XXXIII, Fig. 4) Phalacrocera. — All abdominal segments with long, slender protuberances. .Liogma. 212 Subfamily LIMNOBIINAE I have before ine the larva of one species, and the pupal exuvia of two species, of Limnohia, and the larva and pupa of one species of Dicranomyia. SUBFAMII^Y CHARACTERS Larva. — Head well developed, moderately chitinized. Posterior dorsal slits extending proximad of middle; antennae elongate, base elevated, first joint more than twice as long as broad ; maxillary palpi much shorter than antennae, 2-jointed; labial plate well developed, dentate along its anterior margin ; mandibles stout, with one or two large apical teeth, and a series of smaller teeth along their lower margin on its apical half. Thorax and abdomen without pseudopods, the locomotor organs consisting of a narrow transverse strip of weak hairs or spinules on the dorsal and ventral surfaces of some or all of the segments; in Dicranomyia these locomotor spinules are little stronger than the others on dorsum. Apical segment without finger- like processes; the spiracles in terrestrial forms not in a pronounced depression but capable of being enclosed by the infolding of the apex of the segment; the spiracles in aquatic forms situated in a cleft, with hair-fringed margins, in apex; both terrestrial and aquatic forms with short protrusive blood-gills. Pupa. — Head without protuberances. Thoracic respiratory organs very broad, their length not exceeding their greatest width ; legs much longer than wings. Abdomen with locomotor organs similar to those of larva. Imago. — See key to subfamilies. HABITS OF IvARVAE The larvae of Limnohia are fungivorous and terrestrial ; those of Dicranomyia feed on algae and are aquatic or semiaquatic. A gluti- nous tube is made by the larvae of both genera when nearly or quite mature, and in this pupation takes place. HABITS OF IMAGINES The species of Limnohia usually occur in dense woods where fungi are common ; those of Dicranomyia occur near bodies of water. The species of Gcranomyia frequent flowers, as do the adults of some of the other genera. 213 Keys to Genera LARVAE 1. Apical abdominal segment appearing cleft, the margins of the cleavage fringed with hairs ; body with close pubescence ; apical ventral blood-gills slender, pointed Dicranomyia simulans. — Apical abdominal segment rounded or slightly truncate, not cleft, and without hairs ; body not pubescent ; apical ventral blood-gills stout, rounded Limnohia. PUPAE 1. Thoracic respiratory organs broad, subquadrate, their apices trun- cate, the bases with a hook-like protuberance Dicranomyia simulans. — Thoracic respiratory organs rounded, ear-like, without any hook- like protuberances at base Limnohia. Dicranomyia simulans Walker Limnohia simulans Walker, List of Diptera in British Museum Coll., Pt. I (1848), p. 45. Imago. Dicranomyia simulans (Walker) Needham, 23d Eep. State Ent. X. Y., p. 214. (1907) Larva. — Length, 11-13 mm. Green, with distinct fuscous marks on dorsum which are broken up by small round clear spots and ir- regular clear patches. A close examination discloses the fact that the fuscous areas are composed of closely placed spinose hairs, while the clear spots are either devoid of hairs or yellowish hairs are present. Head large, similar in general appearance to that of Lininohia; antennae long, the shaft about 3 times as long as its greatest diameter; maxillarv palpi short and inconspicuous; labium slightly convex in outline, central tooth much longer and stouter than the first lateral, second and third laterals as large as central. Thoracic and abdominal segments each with distinct anterior marginal fusiform area, these areas not armed with distinct spinules; incisions between dorsal seg- ments of abdomen margined with blackish spinules which are ap- preciably, but not much, stronger than the hairs on the fuscous dorsal markings; apical segment with a cleft appearance, the aperture clos- ing, mouth-like, with the lips vertical. Pupa. — Length, 8-9 nun. More fuscous than the larva. Thoracic respiratory organs as in Figure 5, Plate XXXIII, their structure separating them from any other genus known to me. My onlv specimen is in a fragmentary condition, which prevents me from 214 giving a detailed description. Described from materials obtained by D. K. McMillan at Lake Forest, 111., November 29, 1916. The larva and pupa of this species were described by Needham from this same locality, where they are abundant among algae on the piers, just above and below the surface of the water. LiMNOBiA Meigen GENERIC CHARACTERS Larva. — Head broad, the exposed portion, except for the labrum, subquadrate; antennae of moderate length, 2-jointed; mandibles rather large. Body consisting of 12 segments; dorsal and ventral surfaces with some or all of the segments individually armed with a transverse band of setulae, those on ventral segments situated upon more or less raised transverse ridges or swellings ; apical segment with 2 large, rounded spiracles, without well-defined tubercles, anal ventral blood-gills short, consisting of a pair on each side. Pupa. — Head unarmed. Thoracic respiratory organs in the form of a large disc-like chitinized plate which is attached, ear-like, to anterior lateral angle of thorax ; legs elongated, the hind pair covered almost to apex of basal tarsal joint by the wings, so that only 2 pairs are visible for this distance, apices of tarsi almost in a straight line; wings ending at apices of basal tarsal joints. Armature of abdominal segments similar to that of larva except that the apical segment is slightly chitinized and more or less tuberculate. I can not describe the position of the legs in either of the species before me as only exuvia are available. The figure of hnmatnra is made from a cast pupal skin, and details of the venter of the thorax are incomplete. The spiracles on the abdomen are not well defined, the normal chitinized margin of the openings, so evident in many groups, being absent. In the specimens before me there are, how- ever, two spiracles with distinct chitinized rims on the dorsum of the eighth segment which are connected with stout tracheae. In the specimen of immatura the main tracheae are still visible and each is connected with the integument on the lateral margin of the segments. The apices of the lateral branches appear to connect, by means of a compact mass of thread-like branches, with the wall of the abdomen, and have no distinguishable external aperture. Without a larger amount of material for study I can not definitely state whether these lateral tracheae are functional or not. 215 HABITS OF IvARVAE The only species that I have reared was found feeding in fungi {Agaricus sp.). The species are recorded as fungivorous. Before pupation the larva forms a glutinous tube which is very compact, and in this the pupa is enclosed. The pupa of immatura was found under a bush in woods near Urbana, the larva having very probably fed upon some fungus there. HABITS OF IMAGINES The imagines of many species of this genus are found commonly in woods, flying among the low herbage, and are also frequently taken feeding on nectar of various plants. LiMNOBiA TRiocFLLATA Ostcn Sackcn Limno'bia triocellata Osten Sacken, Proc. Acad. Nat. Sci. Phila., 1859, p. 216. Larva (PI. XXXIII, Fig. 13).— Length, 18-20 mm. White, semitransparent (alcoholic specimens). Dorsum of head with a large blackish patch on each side. Head as in Figures 16 and 17; mandibles as in Figure 6; antennae of moderate length, distinctly 2-jointed. Thoracic segments 2 and 3 each with a large number of transverse series of minute spinules on anterior fifth of dorsal sur- face; first segment with a few microscopic hairs rather longer than the spinules on segments i and 2; ventral surface of the three seg- ments with very similar armature, that on 2 and 3 the more compact, rather longer, and with the areas occupied by it slightly elevated. Abdominal segments 1-7 each with a narrow transverse stripe of short black spinules on posterior margin, the stripes tapering to a point on each side and not reaching lateral margin except in the case of the one on segment 7, which is broad and connects with a similar band or stripe on ventral surface; anterior margins of all segments of venter with a transverse swelling M^hich is armed with stiff black spinules similar to but rather longer than those on dorsal surface, these spinules and those of the dorsal series, without magnification, giving the larva the appearance of having 7 narrow black dorsal stripes and 10 broader ventral ones; apical segment with the large rounded spiracles situated in a slight cavity, the margins of which are slightly irregular but not furnished with well-defined tubercles, the spiracles being capable of entire enclosure by the retraction of the central cavity and the infolding of the margin; apical ventral surface with a pair of short, rounded, retractile blood-gills (Fig. 10). 216 Pupa. — Length, 12-15 mm. Pale yellowish testaceous; head, thorax, and base and apex of abdomen pale brown, slightly shining. Head without armature, front view as in Figure 2, Plate XXXIV. Thoracic respiratory organs reddish brown, similar to those of im- jnatura; wings and legs as described for this genus. Abdominal seg- ments 3-8 each with a conspicuous transverse band of short setulae on anterior margins of both dorsal and ventral surfaces, the bands not connected on lateral margins ; the 2 basal ventral bands widely in- terrupted below legs, the apical one also interrupted, the others com- plete ; abdomen without distinct spiracles except a pair on dorsum at base of apical segment which are connected with stout tracheae; apical segment as in Figures 3 and 4, Plate XXXIV, basal 3 segments and the penultimate dorsally slightly brownish yellow, probably owing to the presence of chitin; apical segment almost entirely brownish yellow. Described from larvae and from pupal exuvia of specimens ob- tained by the writer from a species of fungus (Agaricits) in the fores- try of the University of Illinois, at Urbana, in September, 191 5. LiMNOBiA IMMATURA Osten Sackcn Limnohia immatura Osten Sacken, Proe. Acad. Nat. Sei. Phila., 1859, p. 215. Pupa (PI. XXXIII, Fig. 11). — Length, 20 mm. Color as in preceding species. Differs from it in size, in the structure of the respiratory organs (PI. XXXIII, Fig. 14), and in that the median in- terruption of the setulose band is on the seventh ventral segment. There is also a slight but distinct difference in the structure of the front of the head, as shown in Figures i and 2 of Plate XXXIV; but this may be due to the different sex of the specimens — which in large measure accounts for a difference in the structure of the apical abdominal segments of the specimens (PI. XXXIII, Figs. 11, 12). Described from pupal exuvium of a female. The pupa was found near a bush in Cottonwood Grove, about four miles east of LTrbana, 111., March 23, 1911, and emerged four days later (C. C. Dillon). Subfamily PEDICIINAE With the exception of the larvae of two species, I have no materi- als representing this subfamily, and depend upon the published de- scription of Dicranota by Miall and of Pcdicia by Beling for charac- ters of the pupae. 217 SUBFAMII^Y CHARACTERS Larva. — Head well developed, the dorsum chitinized and with 2 elongate posterior excisions ; labium well developed, in some genera (Pedicia and Dicranota) in the form of 2 plates; mandibles stout, their inner lower margin toothed. Some of the abdominal segments with conspicuous locomotor organs, either in the form of paired pseudopods or elevated transverse areas. Apical segment with 2 long terminal processes. Spiracles situated on dorsum at base of terminal processes. Pupa. — Distinguishable from allied forms by the knobbed respira- tory organs. The ventral segments of the species described by Miall each have a pair of tubercles on the disc, but Beling's description of the pupa of Pedicia rivosa makes no mention of such tubercles. Imago. — See key to subfamilies. HABITS OF I.ARVAE The larvae are aquatic, feeding upon algae and small Crustacea of various kinds, or upon aquatic worms. HABITS OF IMAGINES The imagines are of a rather sluggish habit, and may be swept from vegetation in the vicinity of streams. Their food-habits are the same as those of Eriopterinae. Keys to Genera LARVAE 1. Very large species, 35-45 mm. in length; paired pseudopods con- fined to segments 8-11 ; anal ventral blood-gills very long, about equal in length to the apical processes Pedicia. — Smaller species, not exceeding 25 mm. in length 2 2. Ventral surface of apical abdominal segment with 4 slender pro- trusive blood-gills ; spiracles conspicuous, situated on rather large elevations Dicranota. — Ventral surface of apical abdominal segment without, or with very small, slender protrusive blood-gills; spiracles very small, situ- ated upon small elevations RJiapJiidolahis. PUPAE 1. Ventral abdominal segments without wart-like elevations; large species, more than 30 mm. in length Pedicia. 218 Ventral abdominal segments each with a pair of wart-like eleva- tions; small species, not more than 20 mm. in length. .Dicranota. Pedicia Latreille I have not seen the immature stages of this genus, my informa- tion regarding them having been obtained from published descrip- tions. These justify the following generalizations for the larvae and pupae. GENERIC CHARACTERS Larva. — Head narrow, similar in general structure to that of Dicranota (PL XXXIV, Fig. 9), the dorsal surface compact, arcuate; mandibles slender, the apical tooth long and pointed, inner lower margin with several smaller teeth ; maxillary palpi longer and stouter than the antennae. Body with weak isolated hairs, or bare, the seg- ments distinct ; ventral surface of segments 8-1 1 each with a pair of transverse pseudopods, the apices of which are not armed with spinules; apical segment with 2 long terminal processes, at the base of which, on the dorsal surface of the apical segment, are the spiracles on slight elevations ; ventral anal blood-gills, when fully extended, as long as terminal processes. Pupa. — Differs from that of Dicranota in the absence of ventral protuberances. HABITS OE LARVAE The larvae are aquatic and usually occur in still water — in springs or wells. They feed upon algae, diatoms, and small crustaceans. HABITS OE IMAGINES The flies of this genus are very large, and the wing-markings and conspicuously marked abdomen of the common species render their detection in nature very easy. Their flight is slow and heavy, and they seldom rise much above the level of the rank vegetation in the marshy or wet situations in which they normally occur. Pedicia albivitta Walker Pedicia alhivitta Walker, List of Diptera in British Museum Coll., Pt. I (1848), p. 37. Imago. Tipulid sp.? Needham, Bull. 68 N. Y. State Mus., p. 285. (1903) Needham, in the bulletin cited above, described and figured the larva and pupa of this species. 219 The species is represented in our collection by an imago from New York State. DiCRANOTA Zetterstedt I have the larva of one species of this genus, which is described herein. I have used Miall's description of a European species as an index to the pupal characters of the genus, as this stage is unknown to me. The characters for the separation of the larvae of this genus from those of Pedicia and Rhaphidolabis are summarized in the synoptic key. DiCRANOTA Sp. ? Larva (PI. XXXIV, Fig. 7).— Length, 10 mm. Whitish yel- low. Head black. Head long and narrow, posterior portion in the form of a compact arcuate capsule, the sutures poorly defined except in middle and on posterior margin (PI. XXXIV, Fig. 9). Antennae long and slender (Fig. 6) ; maxillary palpi about the same length as antennae but much stouter ( Fig. 5 ) , the sensory area very distinct ; mandibles long and slender, the apical tooth very acute, inner lower margin with 2-3 smaller teeth ; labium divided centrally, each side with 3 sharp teeth, the median one of each trio smaller than the others. Segments of body well differentiated, clothed with close decumbent pile and with- out distinguishable bristles ; 5 pairs of pseudopods on ventral surfaces of apical 6 segments exclusive of the last one, their apices armed with spines; spiracles situated on a pair of short processes at base of the prolonged apical protuberances; ventral blood-gills short, 4 in number. Described from a specimen taken by Dr. S. A. Forbes among weeds and stones in a stream on Bottlers Ranch, Yellowstone National Park, September 14. 1891. DiCRANOTA BIMACULATA Schummcl Bicranota himaculata Schnmmel, Miall, Trans. Ent. Soc. London, 1893, pp. 235- 253. Larva and pupa. Prof. L. C. Miall published a detailed account of the life history and anatomy of this species in the paper cited above. In general the larva agrees with the one just described, the differences being found in the structure of the head. I have, however, to rely upon Miall's de- scription and figures of the pupa for details of that stage. Pupa, — Thoracic respiratory organs elevated, rather stout, their 220 apices with truncated knobs. The abdomen is furnished upon the middle of the dorsum of the second and sixth segments with a rough- ened plate clothed with short coarse spines, and the intervening seg- ments each have 2 such plates, one before, and the other behind, the middle. Ventral segments 3-7 each with a pair of widely separated papilliform tubercles in a transverse line at middle. Apical segment elongate, without spines. This species is aquatic in the larval stage, but pupates in moist earth along the banks of the streams in which the larvae occur. The larvae feed upon the worm Tubife.v rivtdorum. Rhaphidolabis Osten Sacken I have but one larva that I regard as belonging to this genus. It very closely resembles that of Dicranota, differing in being slightly more slender ; in having the pseudopods armed with a more regularly curved semicircle of apical spinules, the spiracles much smaller and less elevated, the apical processes longer ; and in the apparent absence of the ventral blood-gills. This specimen was taken by Dr. S. A. Forbes among vegetable refuse in Blacktail Deer Creek, Yellowstone National Park, Aug-ust 28, 1890. The larva of R. tenuipes has been figured by Needham*. The species are aquatic in the larval stage, occurring in streams. Subfamily LIMNOPHILINAE I have before me representatives of but one genus of this sub- family, and have found descriptions of but two others of the ten genera which it contains. SUBFAMILY CHARACTERS Larva. — Head well chitinized, much as in Tipula, the principal differences being the much longer maxillary palpi, which exceed the antennae in length, and the less robust mandibles. The labium also shows a departure from the tipulid type and is produced into a rather acute central point anteriorly, but the genera in which the structure of this plate is known to me differ materially, and a generalization is not justifiable, more particularly as both forms are found in other subfamilies. Apical abdominal segment with 4 or 5 protuberances on 'Twenty-third Eep. N. Y. State Ent., p. 201. (1008) 221 margin of stigmatal field ; ventral blood-gills present or absent. Body with short silky pubescence or bare ; bristles absent. Pupa. — Head without chitinized protuberances; palpi straight. Thoracic respiratory organs long and slender, sometimes pointed apically. Legs extending much beyond apices of wings. Abdomen with weak armature, consisting of 1-3 transverse bands of weak spines and some longer slender hairs, or of only weak hairs, the seg- ments with the usual transverse incisions, giving them a divided ap- pearance. HABITS OF LARVAE The larvae of the genus Ula are fungivorous, living usually in Polypori ; those of Limnophila and Bpiphragma are aquatic or semi- aquatic, feeding upon algae and decaying vegetable matter, the last- named genus occuring in dead stems of plants. HABITS OF IMAGINES Most species of the subfamily fly in the evening, and they are not uncommonly attracted to lights. Keys to Genera LARVAE 1. Apical segment with 2 long and 2 short processes which are fringed with very long hairs; labium divided centrally Limnophila. — Apical segment with 4 or 5 short, pointed ]irocesses which are in- conspicuously or not at all fringed 2 2. Apical segment with 4 processes EpipJiragma. — Apical segment with 5 processes Ula- PUPAE 1. Thoracic respiratory organs rather short, swollen at base and acute at apices .' EpipJiragma. — Thoracic respiratory organs long and slender, of nearly uniform thickness throughout their entire length, not acute at apices .... 2 2. A number of hairs on frons between antennae Limnopliila. — No hairs on frons between antennae Via. Limnophila Macquart GENERIC CHARACTERS Larva. — Head moderately chitinized, the ventral, median posterior opening large. Antennae short and slender, with a long apical hair, 222 or 2 such hairs ; frontal plates large ; maxillary palpi longer and much stouter than antennae ; labial plate divided in center, the lateral pieces digitate. Apical segment with 4 long processes which are furnished with long fringes; pseudopods absent. This description applies to aquatic forms only; the terrestrial forms are unknown to me. Pupa. — Palpi straight ; antennae extending to or beyond bases of wings. Thoracic respiratory organs long and slender, least chitinized at apices; legs extending beyond apices of wings, disposed side by side. Abdomen with a number of transverse setigerous ridges on each dorsal and ventral segment, or with distinct tubercles in similar series. HABITS OF LARVAE The only larvae known to me are aquatic. The very long fine hairs on the apical abdominal segment take a very firm hold of the surface of the water when the processes which they border are ex- panded, and it requires considerable effort on the part of the larva to detach them in order to descend. Hart has stated that detachment is accomplished by throwing the cephalic extremity round in such a way that the thoracic segments pass over the apex of the abdomen, and thus their hold on the surface of the water is released. I have frequentlv seen the larvae do this, but only in water too deep for them to get hold of anything in the bottom. A considerable quantitv of air is carried down within the confines of the fringes of the apical processes when the larva descends below the surface of the water, and when this is exhausted the larva ascends for a fresh supply. In cases where the specimens are able to feed without entirely submerging the body, the apical segment is expanded on the surface of the water and forms a conspicuous crater-like cavity within which are visible the eye-like anal spiracles. The food consists of decaying vegetable matter and algae. I have found the larvae common at Muncie and White Heath. 111., but only along the margins or in the muddy banks of streams. I have reared two species, but the larva of only one of them has been associated with the pupa and imago. LiMNOPHiLA LUTEiPENNis Ostcn Sackcn Limnophila luteipennis Osten Saeken, Proc. Acad. Nat. Sei. Phila.. 18.59, p. 236. The larva and pupa are described bv Hart in the paper frequent- ly cited herein*, and the following details should be accepted as sup- plementary to that description. *Bnll. Til. State Lnh. Nat. Hist., Vol. 4, Art. VI, pp. 202-204. 223 Larva (PI. XXIX, Fig. 4). — Length, 15-18 mm. Yellowish tes- taceous or slightly olivaceous. Head dorsally as in Figure 7, Plate XXXIII, the antennae short and slender (PI. XXXIII, Fig. 2) ; mandibles as in Figure 15, Plate XXXIII, being quite different in form from those of Hexatominae and more resembling those of Linmobia; labium (PI. XXXIII, Fig. 3) divided in center, each half with 7 teeth; maxillary palpi with 3 joints. Body with rather conspicuous surface hairs which are situated on slight transverse ridges ; apical segment ( PI. XXX, Fig. i ) with 2 short upper and 2 long lower processes which are fringed with very long hairs; ventral blood-gills 4 in number. Pupa (PI. XXIX, Fig. 5). — Length, 10-13 mm. Color as in the larva. Thoracic respiratory organs (PI. XXXIII, Fig. 18) slightly long- er than wings, their apices split ; legs ending in a straight transverse line at apex of second abdominal segment; each dorsal abdominal seg- ment except basal with 5 transverse series of hair-like bristles set on small chitinized elevations which form slight ridges, the posterior pair much more widely separated than the others. Ventral segments with 6 such transverse series arranged as on dorsal segments. Apical segment of female composed of 2 pairs of elongate processes which form an acute tip, the lower pair two thirds as long as the upper. This species is probably present in every stream and river in the state, as I have found it wherever I have collected in March and April. LiMNOPHiLA TENUiPKS Say Limnophila tenuipes Say, Jour. Acad. Nat. Sci. Phila.. Vol. 3, p. 21. (1823) I have obtained only the pupa of this species. It resembles luteipennis in general shape and in the arrangement of the cephalic and thoracic appendages, but in the armature of the abdomen there is a notable difference. Pupa. — Length (exclusive of the respiratory organs). 10-15 mm. Blackish brown. Thoracic respiratory organs rather more slender than in luteipen- nis. Abdominal segments, exclusive of the basal dorsal, those covered by the legs, and the apical one, each with 3 transverse pairs of widely separated protuberances, the distance between those of each series less than the distance from either to the lateral margins; distance between the most posteriorly placed pair and posterior margin of segment greater than the distance between the pairs ; posterior margin with 224 4-6 smaller protuberances which, like the others, are armed at apices with 1-2 weak hairs; lateral margins with a tubercle at a point cor- responding to the situation of the dorsal and ventral transverse series ; apical segment of male and female as in Figures 8 and 9, Plate XXXIII. I collected a large number of pupae of both sexes of this species on the banks of the Sangamon River at White Heath, III, May 28, 1916. I found that by taking mud from the bank and disintegrating it in the water I could readily obtain the pupae as they floated at the surface. The species is common in Illinois, and probably occurs in most of its streams. The pupa was described by Mr. Hart as Lim- nophila species (a) in his paper previously referred to. Epiphragma Osten Sacken I have not seen the early stages of this genus, but those of fasci- pennis have been described by Needham, as indicated in the synonymy under the species name. ge;nEric characters Larva. — Details of the cephalic structure are lacking in Needham's description, and as I have no means of ascertaining these, only the superficial characters can be indicated. Body cylindrical, without sur- face hairs or bristles; ventral pseudopods represented by fusiform ventral areas; apical abdominal segment with 4 short marginal processes and 4 slender protrusive ventral blood-gills. Pupa. — Thoracic respiratory organs much shorter than in Lun- nophila and IJla, and more horn-like than tube-like, their apices in- curved and acute. Legs extending beyond apices of wings the length of 2 abdominal segments, terminating in an almost straight transverse line. Abdomen without thorn-like armature, only bristly hairs present at apices of segments. Epiphragma kascipennis Say Limnflhia fascipennis Say, Jour. Acad. Nat. Sci. Phila., Vol. 3, p. 19. Imago. (182.3) Epiphrafjjna pavonia Osten Sacken, Proc. Acad. Nat. Sci. Phila., 1859, p. 239. Imago. Epiphragma fascipennis Say, Osten Sacken, Mon. N. Am. Dipt., Vol. 4, p. 194. Imago. (1869) Epiphrapma fascipcnnifi Say, Needham, Bull. 68, N. Y. State Miis., p. 281. Larva and pupa. (1903) 225 Larva (PI. XXXV, Fig. 2). — Length, 19 mm. White, or faintly tinged with yellowish. Head large for the family. (No structural description given hy Needham.) On the ventral side of the three thoracic segments is a pair of minute brownish points. Ventral side of segments 2-7 each with a single median proleg — a mere soft, white, transversely placed ridge, without hooks or claws. The abdomen is without other tuber- cles, spines, or hairs. Spiracles large, widely separated. Spiracular disc with 4 thick marginal processes, the upper pair blunt apically, fringed with hairs, and separated by the full width of disc, the lower pair a little more pointed and a little closer together ( PI. XXXV, Fig. 3). Anal blood-gills slender, 4 in number. Pupa (PI. XXXV, Fig. 9). — Length, 12 mm. Ventral view and general appearance as in figure. Apical carina on each abdominal segment fringed with short stiff hairs, those on the ventral side of eighth segment more comb-like, and interrupted on the median line in female. The foregoing descriptions are abridged from Needham's paper, and the accompanying figures are copied from the same author. The materials used by Needham in making his descriptions were obtained at Lake Forest, 111., where the larvae were found boring in the dead stems of buttonbush and willow lying on the mud at the borders of shallow pools. The species is represented in our Laboratory collection by imagines from Algonquin and Urbana, 111., and from Philadelphia. Pa., all be- ing taken in June. UiyA Haliday GENERIC CHARACTERS Larva. — Body cylindrical, without hairs ; pseudopods faintly in- dicated in the form of slight transverse ventral fusiform areas on apical portion of abdomen. Labium entire ; maxillary palpi longer than the rather stout antennae. Apical abdominal segment with 5 processes on margin of spiracular disc. Pupa. — General appearance similar to that of Limnophila, but the armature of the abdomen differs noticeably in being confined to the posterior margins of the median dorsal segments. Uea eeEGans Osten Sacken TJla elegans Osten Sacken. Mon. N. Am. Dipt., Vol. 4, p. 276. Imago. (1869) Ula elegans Osten Sacken, Alexander, Pomona Jour. Ent. and ZooL. Vol. 7, pp. 1-8. (1915) 226 l,arva. — Length, 8.5-1 1.9 mm. White, the head brownish black, shining. Antennae short and stout, armed at apices with 2 short processes ; labium with a small central tooth, the first lateral on each side dis- tinctly larger and extending anteriorly beyond the apex of the central one, sides of plate sloping abruptly backward, armed with 3 teeth; mandibles stout, their inner margin with 2 teeth in addition to the apical one. Apical abdominal segment with the dorso-central process small, the lateral much longer and slightly more pointed than the latero-ventrals, all fringed with marginal short hairs and each with conspicuous black mark on the posterior surface; anal blood-gills ab- sent. Pupa. — Head without anterior protuberances. Palpi curved slight- ly forward at their apices. Thoracic respiratory organs long and slender, dark basally, pale apically; legs extending to middle of fourth segment beyond apices of wings. Dorsal abdominal segments 2-6 each with a noticeable transverse subchitinized band of a sha- greened texture ; the disc of segments with small setigerous punctures. The above descriptions are abridged from Alexander's, reference to which is given under species name. Alexander's material was ob- tained at Ithaca, N. Y. The larvae feed in fungi, elegans being taken in a species of Pomes (Polyporus) growing on a tree-stump. The imagines emerged in September and October. The species occurs throughout the Atlantic states and is recorded from Wisconsin, so that it probably occurs in Illinois though we have no record of it. Subfamily RHAMPHIDIINAE The only information I have regarding the larval and pupal stages of this subfamily is that contained in the description of the European species BlUptcra oinissa. The larvae of Rliauiphidia longirostris has been found by Gercke, but he did not describe it. The characters of the larva and pupa of BlUptcra as indicated by Mik are given below. One species of this genus, clausa Osten Sacken, occurs in North America. EUJPTERA OMISSA EggCr ElUptera omissa Egger, Vorh. d. zool.-bot. Ges., Vol. 13. p. 1108. Imago. (1863) Flliptcra onnsaa Egger, Mik, Wionor Eiit. Zeit., 1886, p. 337. Larva and pupa. Larva. — Length, 7 mm., breadth, 1.5 mm. More robust than most members of the family, the segments distinctly broader than long. 227 Head heavily chitinized, dorsum with the usual 2 longitudinal dor- sal excisions and a smaller median posterior one. Antennae short and slender. Labium heavily chitinized, triangular in outline, margin den- tate. Mandibles strong, curved, their inner margin dentate. Body slightly flattened dorso-ventrally, the segments distinct, with decum- bent pale pile, and having long bristle-like hairs on lateral margins of each segment, i on the prothorax and 2 on each of the other seg- ments. Abdominal segments 2-8 each with a narrow transverse fusi- form stripe on ventral and dorsal surfaces near the anterior margins which is armed with short spinules. Apical segment tapered, cleft, the margins of the cleavage with 2 upper and 2 lower processes, each pair margined with fine hairs. Pupa. — Length, 6.5 mm. Yellowish brown, the abdomen green- ish white. Thoracic respiratory organs about as long as diameter of thorax, very stout, their bases almost contiguous, tapering from base to apex, and more or less resembling the pincers of a crab. Abdomen armed as in larva except that the lateral hairs are wanting. Legs extending to base of antepenultimate abdominal segment. Apical segment pro- longed slightly in both sexes, that of the female a trifle the longer, a few small processes present in both sexes at base. This genus agrees well in the larval and pupal stages with the cor- responding stages of Dicranomyia, the distinctions between them be- ing less marked than is the case with allied genera of some other sub- families. Subfamily ERIOPTERINAE Helohia and Gnophomyia are the only genera of this subfamily of which identified larvae and pupae are before me. I have, however, an unidentified larva that quite obviously belongs here. There is a great similarity in these larvae, but judging from the available descrip- tions of European species of other genera a great difference exists between the forms I have and those of other European genera. The description of the larva of Trimicra agrees with the characters gen- erally attributed to larvae of Pediciinae — a fact that to my mind throws considerable doubt upon the correctness of the present sub- family-grouping, which is based upon characters of the imagines. I have no intention of rearranging the genera in this or any other sub- familv upon the basis of characters deduced from printed descrip- tions, and accordingly leave the subfamilies practically as in Willis- ton's "Manual", but consider it essential to indicate the probability of errors in the arrangement. 228 I do not include in the following synopsis of characters, nor in my keys, genera which I do not possess, though they may have been de- scribed by other authors ; but notes upon Brioptera are given in the text owing to the existence of a previous record of the occurrence of a larva of that genus in Illinois. SUBFAMILY CHARACTERS Larva, — Slender, cylindrical, tapering slightly towards both ex- tremities, the body covered with dense decumbent pile. Head small, poorly chitinized ; labium unchitinized ; the main portion of head con- sisting of slender chitinized rods, 4 or 6 in number. Pupa. — Head as in Limnobiinae, without projections; palpi straight; directed laterad. Thoracic respiratory organs short, or if of considerable length, still noticeably shorter than those of Limnoph- ilinae known to me, and of a uniform strength throughout; legs longer than wings. Abdomen with weak armature, which is not ^, in the form of transverse bands or series of spinules; spiracles distinct. Imago. — See key to subfamilies. Keys to Genera LARVAE 1. Body witli almost indistinguishable surface hairs; ventral surface of abdominal segments without distinct transverse pseudopod- like swellings • • • Helohia pv.ncUpennis. Body covered with rather long and very dense decumbent hairs which give the larva a silky appearance; ventral surface of ab- dominal segments with distinct transverse pseudopod-like swell- ji^o-s Gnopliomyia fristissimn. PUPAE 1. Thoracic respiratory organs pressed close against surface of thorax; legs extending very slightly beyond apices of wings (PI. XXVIII, ^{g 15) Gnoplioniyia tristis.sima. — Thoracic respiratory organs erect, tube-like, not pressed against sur- face of thorax ; legs extending very far beyond apices of wings . . Helohia pundipcnnis. Heuobia St. Fargeau GENERIC CHARACTERS larva. — Cylindrical, slightly tapering towards the extremities. Head small, entirely retractile, caudad of mandibles consisting of 6 229 chitinized rods with weakly chitinized connecting membrane. Body with very indistinct surface pilosity. First thoracic segment with an indistinct transverse median division. Abdominal segments 2-7 with a median transverse constriction or division. Apical segment with 5 stout protuberances. Pupa. — Differs from the pupa of Gnophomyia in the structure of the thoracic respiratory organs, which are slender and elongate. The legs also are more elongate than in Gnophomyia. HABITS OF LARVAE The larvae are found in mud and sand along the margins of streams. They burrow in the wet sand and are able to live under water like the larvae of IJmnophila, though they are less commonly found there. HABITS OP IMAGINES The imagines are very common throiighout Illinois and usually fly in the late afternoon. They are readily attracted to lights at night. They may feed upon nectar, but the mouth parts are poorly developed. Our species occurs also in Europe. Helobia punctipennis Meigen Limnohia punctipainis Meigen, Syst. Beschr. Eur. Zweifl. Ins., Vol. 1, p. 17. (1818) Larva (PI. XXIX, Fig. 6).— Length. 8-10 mm. Pale yellowish testaceous. Head (PI. XXXIV, Fig. 18) poorly chitinized, the posterior por- tion consisting of slender blackish rods, the intervening spaces filled with weaklv chitinized membrane; antennae short, 2-jointed. the apical joint very short; maxillary palpi longer than antennae and much stouter; mandibles stout, their lower margin toothed (PI. XXXIV, Fig. 11); labium apparently not chitinized, indistinguishable in my specimens. Body covered with short decumbent pile, which is less conspicuous than in the other larvae of this subfamily. Segments with the usual transverse linear incision on dorsum ; apical segment as in Figure 17, Plate XXXIV. Pupa (PI. XXIX, Fig. 7). — Length, 7-9 mm. Color as in the larva. Thoracic respiratory organs tube-like, from 6 to 8 times as long as their greatest diameter; prothorax flattened, declivitous, with an elongate, rather broad foveate mark on each side of dorsum ; anterior margin of mesothorax with a slight ridge-like swelling, upon which are 230 numerous small spinules and, laterally, 2 or more small tubercles ; legs extending well beyond apices of wings, apices of fore tarsi extending beyond apices of mid pair, apices of hind pair extending beyond apices of fore pair. Abdomen without noticeable armature; apical segment of female elongate, the upper processes longer than the lower, that of male obtuse, with 7 slight protuberances, 3 in a transverse line be- fore apex on dorsum and 4 at apex — 2 above and 2 below, the latter acute. The material used in drawing up the foregoing descriptions is that which Mr. Hart had when he wrote his paper on Illinois River species. He did not describe the early stages, referring merely to Beling's de- scription of them which appeared in a European publication. Gnophomyia Osten Sacken gene;ric characters Larva. — Head rather small, wholly retractile, posteriorly com- posed of slender chitinized rods. Body covered with dense silky hairs. General form similar to that of Helohia. the principal differ- ences being the much less conspicuous hairs on the surface of the lat- ter, the absence of distinct ventral locomotor organs, and the longer radiating processes of the apical segment. Pupa. — The structure of the thoracic respiratory organs suffi- ciently distinguishes this genus from Helohia. HABITS OF LARVAE The larvae live in mud, especially along the banks of streams. HABITS OF IMAGINES The flies are usually found in damp situations, especially in grass along the margins of ponds or streams. They feed on nectar or liquids. Gnophomyia tristissima Osten Sacken Gnophomyia tristissima Osten Sacken, Proc. Acad. Nat. Sci. Phila., 1859, p. 224. Larva. — Length, g-i i mm. Slender, slightly tapering towards both extremities, more decidedly towards the cephalic. Body yellow- ish testaceous, covered with dense decumbent pile. Head more compact than that of Helohia, the lateral rods stouter (PI. XXXIV, Fig. 10); antennae very small; maxillae large, pro- 231 duced beyond the apex of the narrow labrum, the palpi stout ; labium not chitinized; mandibles slender, with a long sharp apical tooth and about 3 poorly defined teeth along the lower lateral margin. Loco- motor organs consisting of rather broad fusiform areas on anterior portion oi abdominal segments except basal and apical; hairs along margins of segmental incisions more distinct than elsewhere because of their being slightly curved upward ; apical segment with 5 processes, their structure and markings as in Figure 16, Plate XXXIV; anal ventral blood-gills in the form of 4 short rounded protuberances. Pupa (PI. XXVIII, Fig. 15).— Length, 8-10 mm. Color as in larva. Thoracic respiratory organs very little elevated, in the form of longitudinal ridges very similar to those of some Tabanidae. Protho- rax not so decidedly declivitous as in Helohia. A very long hair on each side of thorax just above and slightly in front of base of wing; front view of thorax and appendages as in Figure 15, Plate XXVIII. Lateral margins of abdomen with long hairs situated upon slight eleva- tions, as shown in figure last mentioned ; spiracles larger than in most genera in the family, 6 pairs distinct; apical segments of male and female as in Figures 16, 17, and 18, Plate XXVIII. The foregoing descriptions are made from specimens supplied by J. A. Hyslop and taken at Wolfville, Md., May 20, 191 3. The larvae are found in wet mud along the banks of streams or other bodies of water. The species is common in IlHnois. EriopTERA Meigen The larvae of two European species of this genus have been de- scribed by Beling. He does not appear to have paid much attention to the structure of the head of any larva that he described, the only characters mentioned being those of general shape, armature, or clothing of the body, the absence or presence of pseudopods, and the shape of the apical segment. The species, judging from his descrip- tion, differ from those of allied genera in having the thoracic segments distinctly swollen and the body noticeably tapered posteriorly. _ The apical segment is armed with 5 short processes as in Gnophoinyia and Helobia. The species described by Hart as Brioptcra species (a) in his paper on the Entomology of the Illinois River, is not an Brioptera accord- ing to this generalization, but is, I think, much more closely related to Gnophoinyia than to BUiptcra, contrary to Mik's opinion^. I figure *Wiener Ent. Zeit., Vol. 16, 1898, p. 62. 282 the head of this species and briefly describe it on a subsequent page of this paper under the heading Genus incertus 2. Subfamily HEXATOMINAE SUBFAMII^Y CHARACTERS Larva (PI. XXXIV, Fig. 14). — Very slender; aquatic or semi- aquatic. Head flattened, not so heavily chitinized as in other sub- families (PI. XXXIV, Fig. 12). Maxillae with a long, slender, pointed process at outer anterior angle, the processes having been er- roneously designated as maxillary palpi by some authors. Antennae short and slender. Labial plate not chitinized, indistinguishable. Mandibles long and slender, sickle-shaped, the teeth confined to base or basal half of inner surface. Body without distinct pseudopods, usually covered with silky hairs; apical segment terminating in 4 slender processes which are fringed with long fine hairs (PI. XXXIV, Fig. 13). Pupa. — Head produced in the form of 2 wart-like protuberances at bases of antennae, bases of the latter, especially in male, swollen, their apices extending to or beyond apices of wings. Thoracic respira- tory organs long and slender, sometimes acute apically; legs extend- ing well beyond apices of wings. Abdomen with a few weak hairs, the segments, except the basal one, usually with a preapical dorsal transverse band of small spinules. HABITS OF IvARVAE The larvae of this subfamily are aquatic, but usually, as is the case with other aquatic Limnobiidae, they pupate in the mud alongside the stream in which the larvae occurred. The food consists of algae and vegetable debris. HABITS OF IMAGINES The imagines of this subfamily which we have observed, are m.ost active in the late afternoon, flying in swarms over streams or along their margins. Usually they are sluggish, and may be swept from rank herbage along stream margins. I do not know their food-habits. Keys to Genera LARVAE 1. Lower process on each side of apical abdominal segment with a very long terminal hair in addition to the fringe of short hairs along margin Pentliopfcra. 233 — Lower process on each side of apical abdominal segment with only the fringe of short hairs, no long terminal hair being present. . ,2 2. Labrum with a leaf-like lobe on each antero-lateral angle which is directed anteriorly and mcsad, the pair almost meeting so as to shield the anterior margin of the labrum Hexatonia. — Labrum either rounded or but slightly produced at the antero-later- al angles, lobes, if present, not directed mesad, and the apices of the pair widely separated Eriocera. PUPAE 1. Apices of fore tarsi ending much proximad of apices of mid and hind pairs Hexatotna. — Apices of fore tarsi ending on a transverse line with mid pair, the hind pair sometimes extending distad of the latter 2 2. Thoracic respiratory organs very noticeably swollen at bases and ap- ices, the constricted central portion with transverse wrinkles .... PentJioptera. — Thoracic respiratory organs of nearly uniform thickness throughout their length, sometimes tapering from near base to apex Eriocera. I have before me a number of larvae of this subfamily, but can as- sociate none of them with a described species as neither pupa nor imago are in the collection. Our specimens, with but one exception, were obtained by Dr. S. A. Forbes in rivers in Yellowstone National Park ; the single one was taken by Dr. C. C. Adams in Montana. The species in their larval stage appear to be confined to swift-flowing streams. No examples have been obtained in Illinois though much careful work has been done on the Illinois River. It is not improbable that an ex- amination of some of the smaller swift-flowing streams in the more hilly sections of the state will discover the presence of these larvae. They are usually found under stones when in the current, but come ashore to pupate in the sand or mud of the banks. The species almost invariably have the appearance of Figure 14, Plate XXXIV, when preserved, the integument of the penultimate segment distending remarkably in some specimens. Brauer, in his paper previously referred to, has figured a species with this charac- teristic distension. The Hng membranous appendages of the maxillae probably serve the purpose of guiding the food into the mouth, being analogous to the mouth-fans of the family Simuliidae — also found in swift-flowing waters. 234 Subfamily TRICHOCERINAE I have before me a single specimen of the larva of a species of Trichocera. The pupa is unknown to me. In many respects the larva resembles that of Rhyphus, but the affinities of the imago are clearly with the Limnobiidae, and for this reason I retain it here, though with some hesitation. Trichockra Meigen GENERIC CHARACTERS Lar^/o-.^Head different from that of all other Limnobiidae in having a complete capsule, closely resembling in this respect Ptychop- teridae and Rhyphidae, the ventral surface especially resembling that of the latter ; mandibles stout, with distinct teeth. Body covered with decumbent pile. Prothorax with distinct spiracles. The apical seg- ment is noticeably more slender than the preceding one and armed with 4 finger-like processes surrounding the spiracles. Pupa. — Head and thorax with hairs much as in Rhyphidae, the cephalic hairs very similar to those of Limnophila. The thoracic re- spiratory organs are horn-like. The abdomen is armed as in Limnoph- ila and has incisions similar to those present in that genus. Imago. — See key to subfamilies. HABITS OF IvARVAE The larvae are found in decaying vegetation and under leaves. HABITS OF IMAGINES The genus Trichocera contains the so-called "winter-gnats" of Europe. Thev fly in mild weather throughout almost the entire winter in Britain, and are frequently seen flying over snow and settling upon it where the sun falls on it. It is remarkable that this very common genus is unrepresented in the materials in our Illinois collection. Trichocera sp. ? Larva (PI. XXXVI, Fig. i). — Length, 7.5 mm. Pale testaceous, the head with brown marks on each side of central sclerite of dorsum in front of antennae, and along posterior margin. Antenna small, consisting of a slender apical process situated on 235 an elevated base; mandibles similar to those of Rhyphidae in that they consist of a stout basal piece and an articulated apical one, the latter with several teeth; labium small, rounded anteriorly, the appendage above it (mentum) similarly shaped, both armed with numerous hairs (PI. XXXVI, Fig. lo) ; labrum overhanging oral orifice, the epi- pharynx armed with numerous strong spinules; maxillae and their palpi similar to those of Rhyphus pimctatus; eyes pigmented, situated on side of head instead of being on dorsum as in Rhyphus. Body with short decumbent pile ; segments of thorax bisected, those of ab- domen trisected ; pseudopods absent ; apical segment with 4 finger-like processes, the lower pair longer than the upper and furnished with some delicate hairs at apices. The specimen descriljed above was taken by A. G. Whitney on St. Paul Island, Bering Sea, March 23, 1913, and formed part of a col- lection submitted to me for identification by the U. S. Bureau of Bio- logical Survey. LiMNOBiiD Larvae of Uncertain Generic Location I have based the synoptic key to the larvae of the subfamilies upon species that T have reliable identifications for, but certain larvae that I have before me are not in agreement with the characters cited, or they so vaguely resemble those that are identified as belonging to the various subfamilies that I have deemed it wisest to describe them in- dependently, in the hope that further Hght may be shed upon their position in the classification by some student of the group who may succeed in rearing them. I realize that there are in store for us many surprises in the larval and pupal characters of species that are as yet unknown in these stages, and hope that the present effort to assign characters for the separa- tion of the subfamilies may be improved upon rapidly after it appears in print. Genus incertus i Larva (PI. XXXV, Fig. 11). — Length, 10 mm. Golden yellow, covered with silky hair which gives the larva a satiny appearance. Ta- pering on thoracic segments towards head. Head almost completely re- tractile, ventral aspect as in Figure 16, Plate XXXV; oesophagus con- spicuous, its sides with very prominent ridges which meet angularly in center ; maxillary palpi 2-jointed, of moderate size ; mandibles barc- Iv distinguishable in mount (see figure last mentioned) ; posterior portion of head consisting of 4 rods, the dorsal pair more elongated 286 than the ventral and thickened apically. Thorax and abdomen dense- ly covered with closely appressed silky pile ; dorsum of thoracic and abdominal segments each with a transverse series of short, closely placed, backwardly directed spines at suture, the abdominal segments with 3 additional transverse series which do not traverse the whole dorsum and are usually interrupted in one or two of the series ; ven- tral segments each with 2 transverse series of similar locomotor spines on all but the apical 4, these latter bearing a series at the sutures and a transverse mouth-like incision with slightly protruded membranous integument which is densely clothed with short upright hairs (PI. XXXV, Fig. 14) ; hairs in front of the transverse incision on apical segment very long ; locomotor spines barely distinguishable except when the larva is alive and in motion ; apical segment terminating in 4 rather long stout processes, on the inner under surface of tiie upper pair of which are the black, round, posterior spiracles, and on the lower pair a long apical hair (PI. XXXV, Fig. 13). The larva just described is one that I took from a much-decayed log at White Heath April 30, 191 6. It conforms to the general characteristics of the larvae of this family, but I have no means of determining its specific identity as the only specimen I obtained died before pupation. The head and thoracic segments were dissected and mounted in Canada balsam ; the remainder preserved in alcohol. The structure of the head points to the likelihood of the species belonging to Eriopterinae. Genus incertus 2 Larva (PI. XXXIV, Fig. 8). — Length, 5-7 mm. Yellowish white, with the head and locomotor areas showing blackish. Head as in Figures i, and 4, Plate XXXV, the general shape re- sembling that of Limnobia; mandibles stout, with apical and lower marginal teeth; labial plate of the same form as in Linmohia. Body, slender, the segmentation distinct; locomotor organs consisting of transverse, elevated, slightly leathery areas which are not armed with spinules, their number and arrangement as in Figure 8, Plate XXXIV. Apical segment terminating in 2 long tapering processes which are armed with a number of long hairs, as in Figure 15, Plate XXXIV. Spiracles situated on dorsum at base of terminal processes, their open- ings not conspicuous nor chitinized. Described from 4 specimens obtained by Dr. S. A. Forbes from Firehole River below Nez Perce Rock Rapids, Yellowstone National Park, August 16, 1890. 237 The description of the larva of Trimicra pilipes Meigen is not un- like that of the present species, but in the former the locomotor organs consist of paired pseudopods, and it is probably a true pediciine species, whereas the one above described may prove to be an aberrant limno- biine, resembling Pediciinae only in the structure of the apical seg- ment. Genus incertus 3 This is the larva described and figured by Mr. Hart as Brioptera species (a). Judging from the characters of the larvae of Brioptera summarized on a previous page this species does not belong to that genus. The head is quite different from that of Helohia, the dorsum being much more compact, as is shown in Figure 19, Plate XXXIV. I believe that the species really belongs to Eriopterinae, as the super- ficial characters ally it more closely with that subfamily than with any other. The larva and its apical segment are shown in Figure 8, Plate XXIX, and in Figure 5, Plate XXX, respectively. For a full description of the species see Mr. Hart's description*. The larva lives among floating weeds in the Illinois River. Genus incertus 4 Larva. — Length, 15 mm. Slender, the segments distinctly longer than broad, the body of almost uniform thickness. Head very similar to that of Helohia, the median posterior rod even more slender than in that genus; dorsal plate (fronto-clypeus) longer and more slender and pointed than in Helohia; maxillary palpi tapering, extending very much beyond the apex of labrum, with dis- tinct constrictions on apical third, giving them the appearance of hav- ing 3 joints. Body covered with dense yellow decumbent pile, most conspicuous at posterior margins of thoracic segments because there it is slightly turned upward. Abdomen without distinct locomotor organs ; penultimate segment swollen much as in Hexatominae ; apical segment with 4 short backwardly directed protuberances, the upper . pair distinctly shorter than the lower ; anal blood-gills inconspicuous. The foregoing description was made from a specimen in the Laboratory collection bearing the accession number 26785, the ac- companying data being as follows : Blacktail Deer Creek, Yellow- stone National Park, August 28, 1890; taken under stones in the water (S. A. Forbes). *Bull. 111. state Lab. Nat. His. Vol. 4, Art. Yj, pp. 198-199. 238 This species closely resembles Genus incertus i of this paper in head-structure and appearance, differing however in the absence of pseudopods. It undoubtedly belongs to the Eriopterinae. Papers on the Biology of North American Limnobiidae* Cylindro tominae Alexander, C. P. '14. Biology of the North American crane flies (Tipulidae, Dip- tera). IL Pomona Coll, Jour. Ent. and Zool., 6:105. (Con- tains full bibliography of the immature stages of the group.) Osten Sacken, C. R. '69. Monographs of North American Diptera. Part IV, p. 296. (Contains synopses of genera and species of imagines.) LimnopJiilinae Alexander, C. P. '15. The biology of the North American crane flies (Tipulidae, Dip- tera). III. The genus Ula Haliday. Pomona Coll. Jour. Ent. and Zool., 7:1. Hexatominae Alexander, C. P. '14. The biology of the North American crane flies (Tipulidae, Dip- tera). I. The genus Eriocera Macquart. Pomona Jour. Ent. and Zool., 6 : 12. '15. The biology of the North American crane flies. IV. Tribe Hexatomini. Pomona Jour. Ent. and Zool., 7 : 141. Family PTYCHOPTBRWAB FAMILY CHARACTERS I^arva.—YiQ:2. s to the various stages of Neniatocera on a previous page. The structure and habits of the species are dealt with under the family, subfamily, or generic headings. *Zoo]. Jahrb., Abt. f. System. Geog. u. Biol., Vol. 40, Pt. 3-4, 1916, p. 307. 246 Superfamily Mycetopliiloidea This superfamily, as at present defined, includes the following families : Bolitophilidae, Mycetophilidae, Sciaridae, Macroceridae, and Platyuridae. The first three families contain, as I believe, the most primitive larval forms known to me, but the fifth has evolved a form that to my mind shows considerable specialization, while the imagines show less specialization, in so far as the wings are concerned, than do those of Mycetophihdae and Sciaridae. The early stages of Macroceridae are unknown to me. SUPERFAMII^Y CHARACTERS Larva. — Head complete, the sclerites, ventrally, more or less dis- tinctly separated, often connected by narrow chitinized strips; mandibles opposed, toothed ; antennae poorly developed except in Bolitophilidae ; maxillae differing from those of other Nematocera in having their inner margins serrate; maxillary palpi developed or un- developed. Larvae peripneustic except in Platyuridae, the latter with- out distinct lateral abdominal spiracles and with protrusive anal re- spiratory gills. Abdomen, and sometimes some or all of the thoracic segments, with locomotor spinules, or the entire body without such organs. Abdominal segments in Platyuridae with conspicuous trans- verse ridges, giving the body an annular appearance. Pupa. — Head small, sometimes retracted, bringing its anterior margin in line with anterior margin of thorax; antennae elongate, either curved over eyes or projecting in a straight line from upper margin of head to base of wing or slightly beyond that point. Thoracic respiratory organs sessile, very rarely elevated. Wings more or less closely adherent to body ; legs long, straight, extending much beyond apices of wings. Abdomen with 6 pairs of spiracles and without dis- tinct armature on dorsum ; apical segment sometimes with 4 short spines. Imago. — The imagines of this superfamily have the radial vein of wings with 2 or 3 branches. The species which have 2 branches only, lack the medio-cubital cross-vein. One of the subfamilies which I have placed in Mycetophilidae has the radius with 3 branches, but the second joins the first and forms a more or less elongated closed cell, and the medio-cubital cross-vein is absent. The antennae are filiform, very rarely thickened, and occasionally remarkably elongated and slender; the proboscis is usually short and fleshy, rarely elongate (Asindiiliim. and Bngnoriste). For synoptic characters see key to imas^ines of Nematocera. 247 Family BOLITOPHIUDAB FAMILY CHARACTERS Larva. — Bolitophila larvae differ from the larvae of Mycetophili- dae in having 2-jointed, v/ell-developed antennae, the head subqiuid- rate, and the median dorsal sclerite truncated apically, its sides on posterior half being little or not at all convergent posteriorly. From the larvae of Platynridae it differs in having well-developed abdom- inal spiracles and the abdomen without conspicuous transverse ele- vated ridges. The pupa is unknown to me. Imago. — Differs from Mycetophilidae in having the radius with 3 branches and in the presence of the medio-cubital cross-vein, from Platyuridae in its distinct medio-cubital vein, and from other families as indicated under the heading "Notes on Family". The species are generallv more fragile than Platyuridae and allied families. HABITS OF LARVAE The larvae are mycetophagous, feeding upon fungi growing upon trees, under logs, or in dense woods or in fields. HABITS OF IMAGINES The imagines are very rare in North America. They are usually found in woods, and particularly along the sides of ditches or .streams in wooded localities, from the grass-grown overhanging banks of which they may often be beaten in spring and fall. They hibernate in these situations in Europe, and very probably in this country also. NOTES ON FAMILY There are but two genera in North America that belong to this family, Bolitophila and Palaeoplatyiira. Hesperinus, which has been placed here, possesses only 12 antennal joints and belongs to the Bibi- onidae. Johannsen expressed an opinion to this effect in his paper on the Mycetophilidae*. The subfamily Mycetobiinae of Johannsen's paper is also, I am certain, composed of genera that are not closely allied. Palaeoplatyiira very probably belongs to Bolitophilidac, where I have placed it, while Ditomyia and Symmerus should f(^rm a fam- ily bv themselves. Palaeoplatyiira is more closely related to Bolitoph- *The Fimgus-gTiats of North America, Pt. T, p. 222. (1910) 248 ila than to Mycetobia, as is evidenced by the complete media, and by the presence of the subcostal cross-vein in P. jolmsoni. Ditomyia and Symmerns both lack the basal part of media and the subcostal cross-vein, while, in addition, the subcostal vein is incomplete. Mycetobia belongs to Rhyphidae. There are two North American species of Palaeoplatyiira, and four of Bolitophila, — two of which, cinerea and hybrida, occur also in Europe. Key to Genera 1. Medio-cubital cross-vein proximad of radio-medial, so that the 2 cells separated by basal portion of media are very unequal in leno-th Bolitophila. Medio-cubital cross-vein almost in vertical line with radio-medial, so that the 2 cells separated by basal portion of media are almost equal in length ". Palaeoplatyura. Key to Imagines of Bolitophila Meigen 1. Fork of third vein ends in first branch of radius (Europe; N. Y.) cinerea Meigen*. — Fork of third vein ends in costa 2 2. Anterior branch of cubitus discontinued some distance from base (Idaho ; N. H.) disjuncta Loew. — Anterior branch of cubitus complete 3 3. Subcostal vein ends in costa at a point above or beyond the base of radial sector— third vein (N. H. ; Ind. ; B. C.) . .Jiyhrida Meigen. — Subcostal vein ends in costa at a point much proximad of base of radial sector (N. H. ; N. Y.) mo7itana Coquillett. Key to Imagines of Palaeoplatyura Meunier 1. Wings unmarked ; subcostal cross-vein absent (Wash.) aldriclii Johannsen. — Wings with grayish or fuscous markings ; subcostal cross-vein pres- ent (Vt.) jolmsoni Johannsen. *The larva of Bolitophila ciAierea has been figured and briefly described by Dr. Felt in the Twenty-ninth Eeport of the New York State Entomologist, p. 67. (1915) Family MYCBTOPHILWAB The limits of this family are somewhat doubtful, and the most recent papers on it seem to me to include a rather heterogeneous as- semblage of genera that require considerable family subdivision. The 249 importance of certain structural details of the imagines is not suf- ficiently realized as yet, and as we gradually accumulate data upon the larval and pupal stages I am confident that certain groups at present considered as genera in the family will be elevated to subfamily, and some even to family, rank. I have taken upon myself the responsi- bility of separating some of the so-called subfamilies from Myceto- philidae — a step which I consider justified because of distinctions which are evident in the adult insects, and also in the known larvae and pupae. FAMILY CHARACTERS Larva. — Head complete, not very heavily chitinized, usually con- spicuously different from the remainder of body in color; antennae usually short, appearing in many genera as pale rounded areas on each side of head near anterior margin ; mandibles toothed ; maxillae well developed, their inner surfaces usually conspicuously dentate; max- illary palpi developed or very slightly so ; labium not in the form of a flat plate ; median dorsal sclerite of head tapering to a point posteriorly. Ventral surface of thoracic and abdominal segments sometimes with a transverse band of black locomotor spinules, which are occasionally very conspicuous; prothoracic and first 7 ab- dominal segments each with lateral spiracles ; apex of abdomen sim- ple ; anal spiracles terminal. Papa. — Head unarmed; antennae curvir.g well over upper mar- gins of eyes, forming a semicircle and ending about middle of wings along their costal margins. Thorax conspicuously elevated, the an- terior margin almost vertical, the dorsum appearing in lateral view ahnost globose; spiracles not elevated; legs elongated; entire f