62 Key to Families of North American Insects. 



5. Mesonotum without a transverse suture; second vein strongly arched forward. 



(Dixa) DIXID^ 



Mesonotum with a more or less distinct suture; female with a conical ovipositor. 

 Crane-flies, Daddy-long-legs 7 



6. Wings ovate or pointed, held folded roof-like against the body, veins very hairy; 



tibiae without terminal spurs; small species. Moth-flies. (Psychoda, 



Pericoma) (PI. 12, fig. 263) PSYCH6DID.ffi; 



Wings narrow, not thus folded against the body; veins scaly; tibiae with terminal 

 spurs; antennae of the males usually feathered with long hairs. Mosquitoes. 

 Culex [C. quinqueja.tciatus. Dengue-fever and Filaria mosquito], Aedes 

 [A. caIopus{=Stegomyia fasciata). Yellow-fever mosquito]. Anopheles [A. 

 quadrimaculatus. Malaria mosquito]) (PI. 12, fig. 267) CULICIDjE 



7. Suture of mesonotum distinctly V-shaped; two anal veins present 8 



Mesonotal suture not distinctly V-shaped, but incomplete or curved; one anal 



vein present. (Bittacomorpha, Ptychoptera) (PI. 12, fig. 269) {LIRI- 

 OPEID^) PTYCHOPTERIDiE 



8. Last joint of palpi whiplash-like, much longer than the three preceding together; 



antennae with rarely more than thirteen joints; auxiliarj^ vein ending in the 

 first vein by an abrupt curvature at the tip, not connected with the first 

 by a crossvein. (Tipula, Pachjn-hma, Ctenophora) (PI. 11, fig. 240; PI. 



12, fig. 273) TIPULIDyE 



Last joint of the palpi shorter or not much longer than the two preceding to- 

 gether; antennae six- to sixteen-jointed, rarely more; auxiliary vein usually 

 ending in the costa and connected with the first vein by a distinct crossvein. 

 (Lunnobia, Erioptera, Limnophila, Trichocera) (including CYLINDRO 

 TOMID^) LIMNOBIID^ 



9. Antennae composed apparently of two joints and a terminal nine- or ten-jointed 



arista; a small but broad second basal cell present; rare small species. 



(OrphnephUa) (PI. 12, fig. 284) ORPHNEPHILID^ 



Outer part of the antennae not formed like an arista; second basal cell absent, 

 or, if present, narrow 10 



10. Wings with a secondary neuration like a fine network of creased lines; slender 



long-legged species. (Bibiocephala, Blepharocera) (PI. 12, fig. 277) 



(LIPONEURID^) BLEPHAROCERID-^ 



W' ings without such secondary neuration 11 



11. Second basal cell present; antennae usually shorter than the thorax, rather 



stout, without constrictions between the joints; eyes of the male often large, 

 ocelli almost always present. (Bibio, Dilophus, Plecia) (PI. 11, fig. 241; 



PI. 12, fig. 266) (including PACHYNEURIDM) BIBIONID^ 



Second basal cell wanting 12 



12. Antennae shorter than the thorax, rather stout, composed of ten or eleven 



closely united joints, never feathery; eyes of males meeting above; body 

 stout, legs strong; anterior veins strong, posterior veins weak. Buffalo- 

 gnats, Black-flies. (Sunulium) (PI. 11, fig. 243; PI. 12, fig. 272) {MEL- 



USINIDM) SIMULIIDiE 



Antennae long and slender, the joints longer than broad, rarely (Ceroplatus) 

 the antennae are flattened; body slender 13 



