Seis O | Q fe 32 ery ae — eet ge eet Se RHE A a a a “ *. % (DIPTERA). ws Be FRED. VW THEOBALD, B.A., F.E.S. CAMBRIDGE UNIVERSITY Are NSION LECTURER IN INJURIOUS INSECTS, ETC. . t VOL. fT. * oe LONDON: ELLIOT STOCK, 62, PATERNOSTER- ROW, E.C. 1892. PREFACE. as 7 THE reason I undertook to publish this book was the almost total absence of any treatise in English upon this much-neglected order of insects. I have dealt with most of the species indigenous to the British Isles, and with many points of general interest relating to the order of *‘ Flies,” also with the characteristics of families and genera, and, where possible, with the life histories of the various groups, especially of those that are injurious to our crops and farm stock. The only English work published on this subject is Walker's ‘“‘Insecta Britannica Diptera,” which is now out of print. It was written more than fifty years ago, and naturally contains much that is quite out of date and inconsistent with the knowledge of the present day. t is hoped that this account may in some way fill up this gap in entomological literature. The author trusts he will be pardoned for the many discrepancies that may have crept in, owing in many instances to his imperfect knowledge of the languages in which most of the literature on this subject is written. For those who wish to go more fully into the subject, the larger works of Meigen (“ Zwei- flugelige Insecten”), Macquart (“‘ Diptéres exotique”), and Schiner (Fauna Austriaca”), together with the numerous papers, articles, and pamphlets enumerated at the end of each family, may be consulted. In a small work of this kind it is impossible to give a detailed description of all the species recorded as British. I have there- fore chosen those about which there seems no doubt, and have omitted many mentioned by Walker as being doubtful. The iv PREFACE. families treated of in this volume are the most difficult and least understood of any, and are in a most unsatisfactory state with regard to their systematic arrangement and identification. It is hoped that this account may spur younger workers on to establish new and important facts, so that inaccuracies may be corrected which naturally will be found in it, and new discoveries made. I have to express my thanks to numerous entomologists for kindly help, and for lending specimens to be figured, especially to Miss Ormerod for the loan of blocks from her ‘‘ Manual of Injurious Insects.” FRED. V. THEOBALD. CAMBRIDGE, 1892. ~~ foal é ‘tat as =~ - 4 . Y Peni =a = 4 ' ; in i — —o a. % Pam 4 eh bs keh) - ey eee ; es * “Mieet La. ee . ‘a, . = ~, = : = ai” CONTENTS. ° pace PREFACE a - ‘ é _ Or Saeas «A SHORT ACCOUNT OF THE MORE IMPORTANT CHARACTERISTICS a OF THE FAMILIES OF DIPTERA - = : 1 ae aa CHAPTER I. ss FOSSIL DIPTERA . : : ~; Sars | CHAPTER II. Bi CLASSIFICATION OF DIPTERA, WITH AN INTRODUCTORY ACCOUNT OF THE ANCIENT AND MODERN CLASSIFICATION OF INSECTA 7 CHAPTER III. ; THE APHANIPTERA, OR FLEAS - : - ; See . CHAPTER IV. _ ‘THE CECIDOMYID&, OR GALL GNATS_~— - - - inl ate £ CHAPTER V. «THE MYCETOPHILIDA, OR FUNGUS GNATS ; ; - 92 CHAPTER VI. THE BIBIONIDE : ; epee 3 - 152 THE SIMULIDE : : : eaters - 165 CHAPTER VII. THE CHIRONOMIDA, OR MIDGES z - : - 169 INDEX - - - - - - - - 207 LIST OF ILLUSTRATIONS. yeu 7 PAGE | o 1. Larva of Pulex felis (canis) - : : dy" 8S 2. Pupa of P. irritans - - - : - 23 3. Imago of Pulex 2 - : : : - 24 4. Head of larva of P. felis (canis) - : - 26 5. Alimentary canal of larva - . - - - 28 6. Catocha latipes - “ : . : ae 7. Balancer of Cecid - - - - - - 40 8. ¢ Genitalia ofa Cecid - - - - - 41 g. Larva and pupa of Cecidomyia_ - - : 5 ro. Anchor process of Hessian Fly and Wheat Midge - - 46 11. Aristolochia clematis, showing method of fertilization - 49 12. Galls produced by some Cecidomyide - - ee 13. Mouth parts of AZycetid larva - - - + ye 14. Larvee of Sciophila, acacia and Sciara - - 96 15. Pupaof Sciara_ - - : - 97 16. Alimentary canal: of Mycetid larva (Mycetophila) - - 100 17. Head and antenna of Asindulum, and head of Sciara - 100 18. Boletina dubia - - - . - =~ $6 19. Three types of venation in Sciara - - - - 107 20, Wing of Bradysia - . - - : FF 3 | 21, Lpidapus venaticus - . - - - 113 | 22. Wing of Zygoneura- - . : - - 84 | 23. Mycetophila cingulum - - - - - 116 24. & Genitalia of Phronia_ - - : - - 126 : 25. 9 Genitalia of Phronia - - - - - 128 : 26. Head of Leptomorphus Walkeri - : : - 133 27. Head of Zetragoneura Sylvatica - : . - 136 : 28. Sciophila Fasciata - - : - . - 139 29. Ceroplatus lineatus- - - - : - 143 . Antenna of a AWacrocera ? : - . - 144 WwW oO Wing of Ditomyia fasciata- Wing and palpus of Diadocidia rami - | Dilopus febrilis, or Fever Fly | —Simulium reptans - . Larva of Chironomus plumosus Eggs of Chironomus | Pupa of Chironomus plumosus Clunio marinus Larva of Ceratopogon bipunctatus _ Pupa of Ceratopogon bipunctatus Compontia cruciformis Three undescribed larvze of Chironomus (ep. ?) eee abe a ieg and paps * oer Us » 9 DESCRIPTION OF PLATES. ~ 7 PLATE I. WINGS OF SOME CECIDOMYID. Fic. 1 (= 1a) Cecidomyia. Fic. 2 (= 2A) Diplosis. » 3 (=34) Epidosis. » 4 (=4A) Asynapta. »» 5 (=5A) Catocha. », 6 (=6a) Campylomyza. »» 7 (=74) Lestremia. » 8 (=8a) Colpodia. » 9 (=9A) Spaniocera. ,, 10 (=10A) Lasioptera. PLATE II. CECIDOMYID&, Fic. 1. Hormomyia fasciata. Fic. 2. Lastoptera rubi. » 3+ Micromytia globifer. » 4 Antenna of H. fasciata. » 5. Antenna of LZpidosis ,, 6. Antenna of Campylomyza gracilts. halterata, : . Antenna of WDéplosis ,, 8. Antenna of Asphondylia buxt. sarothamnt. Antenna of Lestremia Carnea. PLATE III. BIBIONIDA. Larva of Bibio pomone. Fic. 2. Pupa of B. pomone. . Leg of Anarete albi- ,, 4. Wing and antenna of pennis. Scatopse. . Antenna, wing, and leg ,, 6. Bibio marci (leg and an- of Aspistes berolinensis tenna). . Wing, leg, and antenna of Dilophus febrilis. ee IV. CHIRONOMIDA, Fie. 1. Corynoneura (antenna FIG, 3. Anal segment te ‘ of g and ?). tarsus. ey 9, 2 Antenne of C. plumosus, 5, 5. C. plumosus. | Sa 2 g. ee | » 4. Antenna of Diamesa » 6. Wing and intenna tonsus. Tanypus monilis. » 7. Antennaof Cluniomari- ,, 8. Ceratopogon illustris. nus. » 9. AntennaofMetriocnemus ,, to. Antenna of C. jue re. lacustris. a ‘ae A SHORT ACCOUNT OF THE MORE IMPORTANT CHAR- ACTERISTICS OF THE FAMILIES OF DIPTERA. eo > Family Pulicde. Parasitic insects, with scale-like rudimentary wings ; long legs, very large coxze, tibiz spurred. Eyes may or may not be present. Thorax composed of three distinct segments. Family Cecidomyide. Ocelli often absent. Thorax with no transverse suture. Antennz moniliform, 24-jointed in ¢, 12 to 14 inthe 2. Wings with only few nervures. Coxze not elongated, femora not thickened, no spurs on tibie. Family Mycetophilide. Ocelli two or three ; often so small they can only just be discern- ible. Thorax with transverse suture. Antennz usually 16-jointed. Eyes generally round. Few nervures in wings, no discal cell. Tibize spurred, coxze elongate. Family Brbionide. Ocelli three. Thorax without transverse suture, pro-thorax largely developed. Eyes of ¢ large and contiguous, smallin 9. Antenne g-jointed. No discal cell in wings. Feet armed with long em- podium, pulvilli present in some genera. Family Simulide. Ocelli none. Thorax without transverse suture. Posterior tibiz and first joint of hind tarsi dilated. Antennz cylindrical, 11-jointed. Family Chironomide. Head small, retracted; often partly covered by thorax. Ocelli none. No transverse suture on thorax. Eyes reniform. Antennze from 6 to 15 joints; pectinate in 4, simple and composed of fewer joints in ¢°. Wings without vein along the posterior margin ; costal vein ending near the tip of the wing. xii SHORT ACCOUNT OF THE MORE IMPORTANT Family Orphnephilide. Ocelli absent: Head small, round; eyes round. Costal vein continued round the posterior border of wing. Family Psychodide. Ocelli absent. Body with long, coarse hairs. No transverse suture to thorax. Antenne long, 16-jointed. Wings very broad and hairy ; many longitudinal veins, only a few transverse veins ; no dis- coidal cells. Legs long, tibize without spurs. Family Culicide. Ocelli none. Thorax with no transverse suture. Head small. Antenne long, 15-jointed ; pectinate in g. Costal vein continued round margin of wing, fringed with scales ; veins in their last sub- divisions more than six in number. Family Dixide. Ocelli wanting. Head rounded. Antennz long, 12-jointed ; basal joint thick, flagellum slender. Family Zipulide. No ocelli. Thorax with V-shaped transverse suture. Antenne long, composed of 6 to 19 joints. Basal cells of wings reaching beyond the middle. Discal cell generally present. Legs long and slender. Family Rhyphide. Ocelli three. No transverse suture on thorax. Antenne as long as thorax; 16-jointed. Wings with a perfect discal cell, large and broad. Empodium like a pulvillus, pulvilli wanting. Family Stratiomyide. Head short, as broad as thorax. Third joint of antenne annu- lated ; furnished with a terminal bristle. Ocelli present. Three basal cells, much prolonged. Veins of two main trunks very crowded anteriorly. Costal vein reaching only to middle of wing. ‘Tibiz spurless. Empodium large, resembling pulvillus. Family Xylophagide. Head short and broad. Third joint of antennz annulated; no terminal bristle. Three basal cells, very prolonged. Third longi- tudinal: vein furcate; both intercalary veins present. Marginal vein encompassing the whole wing. Tibize with spurs. Empodium as above. CHARACTERISTICS OF FAMILIES OF DIPTERA. xiii Family Zabanide. Three basal cells, very prolonged. Third longitudinal vein furcate. Two intercalary veins always present; marginal running around whole border. Tegulz large. Head broader than thorax. Third joint of antennz annulate, generally entire; no terminal bristle. Proboscis strong and prominent. Empodium large, pulvilliform. Family Leptide. Head smaller than in Tabanidz. Antennz short, last joint rounded, furnished with terminal bristle. Family Astdide. Three basal cells, much prolonged. Third longitudinal vein furcate, and the two intercalary veins present. Head short and broad; eyes prominent. Third joint of antennze simple. Thorax narrowed in front. Empodium like a horny bristle. Family Bombylide. Three basal cells much prolonged; the anterior intercalary present, the posterior always wanting. Proboscis prominent, long and slender. Third joint of antennz simple, generally provided with a bristle or tuft at the end. Empodium rudimentary. Family Z) herevide. Three basal cells prolonged; both intercalary veins present. Third longitudinal vein furcate. Antennze with short terminal bristle. No empodium. Family Scenopinide. Three basal cells, very large ; the third closed far from the border of wing. No intercalary vein; third longitudinal vein furcate. Antennz with third joint very long, no terminal bristle. No em- podium. Family Cyrtide. Eyes very large. Tegulz vaulted, very large. Basal cells long. Neuration very variable, often incomplete. Terminal antennal joint simple. Tibiz spurless. Empodium large, pulvilliform. Family Zmpide. Three basal cells complete, large ; the third shorter than second. Posterior basal transverse vein parallel to border of wing. Anterior intercalary present, posterior wanting. Antenne with first two joints very small, hardly distinct; third not annulated ; often with a ter- minal bristle. Empodium membranaceous. xiv SHORT ACCOUNT OF THE MORE [IMPORTANT Family Dolichopodide. First basal cell rather short, the second united with discal cell, third small. Auxiliary vein running in the first longitudinal. Third vein simple; fourth often furcate. No intercalary vein. Em- podium small, membranous. Antennz close together; third joint not annulated, with bristle at tip. Family Lonchopteride. Three basal cells of moderate size, nearly equal in length. Fourth longitudinal vein furcate, and united with fifth near the base. First two joints of antennze small, testaceous ; third rounded, witha slender apical bristle. Empodium wanting. Family Platypezide. Three basal cells rather large, the hindermost always ending acutely at more or less distance from the border of the wing. Third longitudinal vein simple. No intercalary vein. Antenne with apical bristle. Empodium wanting. Family Pipunculide. Three basal cells much prolonged, the hindermost closed near the border of the wing. Fourth vein may be absent, furcate when present. No intercalary vein. Eyes large, not quite contiguous in ¢. Antenne short, with a basal bristle. Legs with few short spines. Empodium wanting. Family Syrphide. Three basal cells much prolonged. Third longitudinal vein simple ; a spurious longitudinal vein between third and fourth ; fourth united at its end to the third ; no intercalary veins, Antennz close together; third joint various, generally compressed and with a bristle on its back. Hypopygium unsymmetrical. No empodium Head semicircular, as broad as thorax. Family Conopide. Three basal cells, large, third closed, more or less remote from the posterior border. All the longitudinal veins simple; no intercalary vein. Head large, always broader than thorax. Antenne long ; third joint clubbed and ending in a bristle. Hypopygium symmetrical. Em- podium wanting. Proboscis generally prolonged. Eyes not con- tiguous. Family Gsétride. Antennz inserted in round pits. Oral organs rudimentary. Tegule large. Antennz short; third joint with a terminal bristle. Very hairy flies, resembling bees. | CHARACTERISTICS OF FAMILIES OF DIPTERA. xv Family Zachinide. Antennal bristle bare, or covered with minute pubescence. Thorax short. First posterior cell closed, or only faintly open. Abdomen more or less oval, beset with bristles. Legs short. Family Dexide. Antennal bristle hairy or pectinated. Thorax short. First pos- terior cell as above. ‘Tegulz large. Abdomen with long bristles on at least the last two segments. Legs long. Family Sarcophagide. Antennal bristle plumose or hairy ; apex bare. First posterior cell as above. Tegule large. Legs stout. Family Muscide. Antennal bristle entirely plumose or pectinated. Body stout, thorax short. First posterior cell only slightly opened or else closed at the border of the wing. Family Anthomyide. Antennal bristle naked or pectinated. Thorax with a complete transverse suture. First posterior cell fully open. Tegulz not very large. Abdominal bristles often absent. Family Cordyluride. Neuration complete. Both posterior basal cells large. Auxiliary separated from the first longitudinal vein. Whole lateral border of the front bristly ; anterior border of mouth with numerous strong vibrissz. Family Phycodromide. Front bristly ; border of the mouth hairy, with no distinct vibrissz. Legs stout ; tibize with spurs, and each with a small bristle on the outside, near the tip; the first joint of posterior tarsi not abbreviated : last joint of all the tarsi enlarged, with stout claws and long pulvilli. Costa without bristles ; basal cells not small. Family Helomyzide. Front bristly on its upper half only. diets oF ise vd a) sos +) he 7 y o . a 23 , yak t. ay 4 iF 7 ee WEY * a af ey Ping J a Fo : ee SS : bh 4 : ; Mh waar . : - ie : a ~*~ =" a ; ; ‘ehed om - cHaac CTERIS TICS OF FAMILIES OF DIPTERA. xix | Family ippoboscide. "Body horny and flattened. Head flattened. Antennze composed of one joint only, and furnished with terminal bristle. First joint of all, or, at least, of the anterior and middle tarsi, abbreviated. Family Braultda. Wildes and blind ; parasitic on hive bee. Family Wycteribide. _ Antenne short, 2-jointed. Head not flattened. First joint ot all the tarsi long, or very long in comparison with the following. Eyes present. Spider-like. eS en ERRATA. Page 12, line 28, for ‘* Centis” read “ Curtis.” . Page 15, insert ‘* Anisomerinz ” in Fam. 11. , Page 16, Fam. 31. for ‘‘ Desidee ” read * Dexidee.” : Page 16, insert ‘‘ Fam. Leptidee”’ after “ Tabanide.” j Page 23, line 8, also pages 25 and 32, for “ pupiate” vead “ pupate.” Page 31, Sho cig gallinaceus belongs to a perfectly distinct genus to P. gallina. Page 32, line 12, for “‘ Antenne” read “ Palpi.” Page 35, line 20, for “* Palicide” read ** Pulicidze.” Page 39, fig. 6, for “Catacha” read * Catocha.” Page 78, line 1, for “ingulbine” read “ inquiline.” Page 86, line 27, for “‘ Rud” read * Rnd.” Page 93, line 13, for “ States” read “ Slates.” Page 96, line 13, for “larvae” read “ larva.” Page 172, line 23, and page 173, for “‘Grumm ” read “ Grimm ” AN ACCOUNT OF BRITISH FLIES (DIPTERA). _ 77 CHAPTER I. FOSSIL DIPTERA. One of the branches of science that has advanced with rapid strides during recent years is geology; in all quarters of the globe fresh discoveries have been made, which have entirely altered many of the old theories and beliefs. We have here only to deal with one branch of geology, namely Palzontology, or the study of fossil animals and plants. At the end of the last century William Smith, a land surveyor, laid the foundation of Paleontology. He showed that strata could be traced and identified by their included fossil animal remains, and in 1815 he published his work on “Strata Identified by their Organic Fossils,” and thus laid the foundation of a new branch of geology that was destined to take the place of mineralogy as the handmaid of geology. From this time onwards continual advances have been made in palzeontological study, in all parts of Europe and America. England has been especially to the fore in this respect. It is, however, com- paratively recently that insects have attracted the attention of fossil collectors. We owe our knowledge chiefly to Scudder, Brodie, Heer, Loew, etc. Scudder has published a good account in the American Government Reports. Brodie had, however, previously written on the Mesozoic and Tertiary insects, and had figured a good many specimens. Prior to giving an account of the fossil Diptera it seems well to append a short description of the order. I 2 AN ACCOUNT OF BRITISH FLIES. Order DIPTERA. Mouth suctorial, and used for piercing, the labium being greatly developed and forming a gutter for the reception of the lancets {maxillee and mandibles). This proboscis, which is chiefly made up of the labium, ends in a fleshy swollen tongue, and is without palps. It is closed above by the labrum. The maxille are provided with palps; the- mouth, however, may be obsolete or closed. The head is usually large and spherical, and is attached to the thorax by a short neck. Two large facetted eyes are present, and there may be ocelli as well. In the ¢ the eyes may join in the middle line, this being a valuable way to distinguish sex. The antenne are of two forms, («) long and filiform, and composed of many joints ; or (8) short, with the third joint inflated, and bearing two or three tapering joints or a bristle. The thorax is usually large and compact ; the prothorax very much reduced, and attached as a collar to the mesothorax, which is very large and is developed at the expense of the other two regions of the thorax. One pair of true wings only developed, these being the anterior ones, and are usually transparent and never folded, with an inferior basal lobe. Veins crowded in front, distant behind. Cross veins few. The hind wings reduced to small club-shaped laminz, known as halteres. Both may be absent. The abdomen generally small, but may be elongated, as in the Tipulidz, and composed of five to nine segments. Legs six in number, and slender, having five jointed tarsuses, ending in ungues or “‘pads” for attachment. The nervous system presents various modifications—in some the ganglia of the thorax and abdomen become fused, or there may be three thoracic ganglia and five or six abdominal ganglia. The male genital organs consist of two testes with vasa deferentia and copulatory appendages. The female have three receptacula seminis in connection with the vagina, and in some cases have a retractile ovipositor. Having given a short general description of the Diptera we can now pass on to the review of the fossil species. In dealing with the ancestral forms of our flies, we include those found in all parts of the world, as very few have been discovered in England, compared ee ee ma ln Oe te aa FOSSIL DIPTERA. 3 with the number that have been found on the Continent and in America. One of the chief modes of preservation is in amber, the greater number of species having been found in this state. The earliest recorded occurrence of Diptera is in the Mesozoic period, although insects appeared in the early Palzozoic period. The extreme fragility of insects renders their preservation difficult, and we therefore find but a very scanty representation of the Dipterous fauna. It will be only possible here to give a short account of the genera, many of which are described only from such fragmentary remains as wings and other detached portions. a&,-— BRACHYCERA, Fam. Dolichopodida.—The members of this family are very abund- ant in the fossil state, being beautifully preserved in amber. Particular attention has been paid to these by Loew, who has enumerated nearly seventy species of Dolichopus, Rhaphium, Potlopus, Medeterus, and Chrysotus. The genus Dolichopus has also been described from Wyoming. Fam. Hmpide.—This family has been figured by Brodie from the Wealden of England ; and, according to Giebel, the species described belongs to a new genus—Hasmona. Loew has described the genus Ampis from the Rhenish coal and sixteen from amber. Giebel, Heer, and Loew have described many other genera besides these from the amber of the Tertiaries. Fam. Lombylide.—Alone found in the Tertiaries, the genus Anthrax being found at Oeningen;and on the Rhine. They are mostly found in amber. Fam. Asi/ide.—Brodie describes an Asi/us from the Lower Lias, and Germar another (Asv/icus) from the oolite of Solenhofen. These are the only two recorded Mesozoic species. In amber the Asilidz are more abundant. Many are described from Oeningen and in Sicilian amber. Fam. Leptide.—This family is rare in a fossil state. One species has been recognised in the Eocene of the Isle of Wight. Fam. Zabanide.—The Swiss geologist, Heer, describes and figures one of this family from Oeningen, and it is also reported from the Rhenish coal. Fam. Stratiomyide.—Both perfect insects and larve have been found in the Tertiary and Quaternary deposits. They have mostly come from Aix, where Serres recognised Oxycera and Sargus. 1—2 4 AN ACCOUNT OF BRITISH FLIES. Oustalet also describes a species of Stratiomys from Pontary in the Miocene deposits. 8.—NEMATOCERA. Fam. Rhyphide.—Brodie has figured a species of this family from the English Purbecks under the name of Ahiphus priscus. It is more abundant in the Tertiaries, and is described by Heer. Fam. Zipulide.—We now come to a very abundant family, both in present and past times. The Tipulide attained great variety in the Tertiary period, which contained many that are now entirely extinct. The Tipulidze are recorded in the Oolite of Solenhofen by Weyen- bergh, and from the Lias and Purbecks by Brodie, Westwood and Murchison. I have also found a specimen in the Wealden, although in a very imperfect condition. A great many are also recorded from that great storehouse of insects of Tertiary times—viz., amber. Loew has found as many as sixteen species of Tipule in amber, one of Macrochile and four of Dixa. Tipule has also been reported from Aix, Utah, and Italy, and also from Sicilian amber. It has also been recognised in the Eocene of the Isle of Wight and the larval form at Sieblos. Fam. Chironomide.—These delicate little flies have been preserved since Mesozoic times, where they seem to have been of not un- common occurrence. But it is not until we get to the Tertiary ambers that we find them in any abundance. They are recorded from the English Purbecks and from the Lias of Dobbertin, It is also probable that Ahyphus priscus, described by Brodie, and men- tioned above, belongs to this family, and not to the Rhyphide. If so, this adds another one to the list of Mesozoic forms of this family. Fam. Culicide. —'Two imperfect specimens from the English Purbecks are referred by Brodie to this family. One to the genus Culex, namely, C. fosszlis, has the antennz and legs well preserved, but the wings are entirely absent. Of course, the amber has preserved many genera and species, especially in Aix and Utah, and in the Tertiaries of the Isle of Wight. Fam. Bibiontde.—This family is reported to occur in Mesozoic strata by Geinitz, who figures a species under the name of Protomyia dubia, from the Lias. Scudder, however, says this is not a Dipteron at all. So we must at present only consider this family as a Tertiary one. But in Tertiary times this must have been a very abundant sa cl dal FOSSIL DIPTERA. 5 family, especially in specimens, but not so in species, for as many as a thousand specimens have been alone found at Florissant, according to Scudder. But amongst these thousand there are only fifteen to twenty species. Bibio is one of the most plentiful genera, and is abundant at Oeningen. They are rare in amber, but abundant in the Tertiary rocks. | Fam. Simudide.—In the Purbecks of England two species of this family have been preserved, namely, Stsmulium humidum and Simu- lium priscus. Others are also found in the Tertiaries. Fam. Mycetophylide.—This family, again, is found in the Mesozoic period, several genera having been described by Brodie under the names Platyura = Adonia of Giebel, and Macrocera = Sama of Giebel. Another genus, Z/zras, now extinct, has been figured by Westwood. In the Tertiary formations these flies appear abundantly, many of which are now extinct as generic types. They are found both in the amber and Tertiary rocks, the species being generally distinct in the two modes of preservation. For instance, Sciobia, Aclada and Heterotricha are genera peculiar to the amber, not being found in the rocks. A great number of species have been described, and from very wide localities, especially from Aix, Utah, Wyoming, Oeningen, Florissant, and England. Fam. Cecidomyide.—Members of this family have mostly been found in amber, there being no record of them in Mesozoic times. Fam. Syrphide.—It is somewhat doubtful if this family is really represented in time earlier than the Tertiary. ‘Two species have been referred to the Syrphidze from the Mesozoic rocks; one from the renowned rocks of Solenhofen, which, according to Weyen- bergh, is a Chezlosta, another has been figured by Brodie from the Purbeck that may possibly belong here, but being only fragmentary, its true nature remains very doubtful. The following genera are present in the Tertiary beds, viz., Xylota, Chetlosia, Volucella, Rhingia, Sprphus, and Eristalis. The following table, taken from part of Scudder’s table of the Geological distribution of insects in his systematic review of their fossil remains, shows the range and time of origin of the four great divisions of Diptera. AN ACCOUNT OF BRITISH FLIES. Trias. Lias. Oolite. | Cret. ||Tertiary. || Recent. Diptera: | Ts "EEPLOPOSCIGGa: | sess overs) saswsswnewer|esanes scanaypenveaneses