N'O. 64] DIPTERA or CONNECTICUT : MORPHOLOGY 11 



may be seen by comparing the broad, greatly flattened body of a 

 nycteribiid, streblid, or hippoboscid, with the markedly compressed 

 body of certain mycetophilids, or by comparing the compact thickset 

 body of a cyrtid with the extremely slender elongated body of a tipulid 

 of the genus Tanypreinna^ which apparently includes the slenderest 

 species of Diptera. The somewhat slender type of body characteristic 

 of most Nematocera is evidently the primitive one, while the more ro- 

 bust type of body is encountered in the higher Diptera. 



Variations in the structure of the head, thorax and abdomen will 

 be described under the detailed discussions of these regions of the 

 body, but since the modifications of the wings are not discussed under 

 these headings, it may be of interest to point out some of the modi- 

 ficational extremes occurring in the development of the wings. In the 

 remarkably aberrant nematocerous fly, Nynvphomyia alba, recently de- 

 scribed by Tokunaga (1932b) — shown in Plate 34 of Vol. 13, Annota- 

 tiones Zool. Japonenses — the wings are extremely long and slender and 

 are bordered with very long hairs to compensate for the loss of wing 

 surface necessary for flight. In the peculiar anthomyid, Exul sing- 

 ularis, on the other hand (see Plate 2 of the ''Insects of Australia 

 and New Zealand" by Tillyard, 1926), the wings are enonnously ex- 

 i^anded, and their breadth almost equals their length in this peculiar 

 fly. In the asilid, Eurhahdus zephrjrea, shown in Fig. 140, p. 182 of 

 the "North American Diptera" by Curran (1934), the basal half of 

 the wing is narrowed to form a long slender petiole, while in the 

 helomyzid Griddlerlu hemiptera, shown in Fig. 16, p. 381 of the same 

 book, the distal two-thirds of the wing becomes drawn out into a long 

 slender process. 



The winga are usually well developed in the tipulicls, but they are 

 vestigial in the tipulid Ghionea which lives on the snow, and both 

 wings and halteres have completely disappeared in the tipulid Lvmno- 

 phila ( Roraiinoinyia) perm.onstrata, although the halteres are usually 

 retained when the wings are lost. Comstock (1924), in his 'Tntroduc- 

 tion to Entomology," p. 793, states that both wings and halteres are 

 absent in the mycetophilid Pnyxia (female), and also lists the Chiro- 

 nomidae, Phoridae, Borboridae, Ephydridae, Nycteribiidae, Hippo- 

 boscidae and Braulidae, as the families in which the wings may be 

 vestigial or wanting. A more nearly complete list is given by Brues 

 and Melander (1932, p. 347-352), who likewise include the Cecido- 

 myidae, Scatopsidae, Chiromyzidae, Termitoxenidae, Thaumatotoxen- 

 idae, Empidae, Dolichopodidae, Ephydridae, Drosophilidae, Dry- 

 omyzidae, Caelopidae, Anthomyidae, Micropezidae, Chloropsidae, 

 Streblidae, etc., as the families in which wingless forms, or those with 

 vestigial wings, may occur. 



No comprehensive studies of the entire external morphology of 

 the Diptera in general are available at the present time, although Hen- 

 del (1928) has discussed many characters of taxonomic importance in 

 the Diptera, and Walton (1909) describes the head and thoracic struc- 

 tures of the higher Cyclorrhapha in connection with the chaetotaxy 

 of these parts (see also the morphological sections of Townsend's 

 "Manual of Myology"), while figures of the heads, wings, etc., of var- 



