NORTH AMERICAN DIPTERA. 



3. Proboscis projecting, horny, the labella slender and pointed, turn- 



ed backward, hook-like; arista pubescent; eyes bare; moderate 



sized, blackish species. .... Drymeia. 



Proboscis not horny and hook-like. ..... 4 



4. Abdomen of male ovate or conical; second segment not longer than 



the third, the first segment usually imperceptible. . . 5 



Abdomen of male elongate, the second segment longer than the 

 third; first segment usually distinctly visible. ... 12 



5. Eyes pilose (1) (Phaonia] Hyetodesia. 



Eyes bare. .......... 6 



6. Arista plumose. ......... 7 



Arista bare or pubescent. ....... 8 



7. Abdomen ovate, not spotted. ..... Mydaea. 



Abdomen subconical, usually spotted (1O, 11, fig. 135.)- 



Spilogaster. 



8. Front femora of the male with tubercles or emarginations below, 



or otherwise peculiarly constructed; front tibiae often with 

 emarginations; hind femora often arcuate; middle and hind 

 tibiae sometimes with tufts of hairs; black or blue-black flies, 



often pollinose Hydrotaea. 



Front femora simple in both sexes. ..... 9 



9. Abdomen shining black or metallic black (9). . Ophyra. 

 Abdomen not shining black or metallic, and with markings. 10 



10. Vibrissae at some distance above oral margin. Brachyophyra. 

 Vibrissae inserted at oral margin. . . . . . .11 



11. Fourth vein nearly or quite straight (16).* . Limnophora. 

 Fourth vein distinctly curved forward (12, 13). Leucomelina. 



12. Eyes pilose. ....... Trichophthicus. 



Eyes bare. .......... 13 



13. Anal cell short; axillary vein roundly curved toward it (7, 8). 



Homalomyia. 

 Anal vein long, often reaching the wing margin. . . 14 



14. Arista plumose (28, 29). .... Hydrophoria. 

 Arista bare or pubescent. ....... 15 



15. Oral margin and under side of head thickly clothed with bristly 



hairs Pogonomyia. 



Not thickly covered. . . . . . . . .16 



* Compare Hammomyia. 



