12 Familiks and Gkneka or- 



19. Antenna? npparently single-jointoil, with a long bristle; winj^s 



with several stout veins anteriorly, and other weaker ones 

 running across the surface unconnected by cross-veins ; fem- 

 ora flattened, the hind legs long; antennas situated near the 

 mouth; small, quick-running, hunchback-like flies. riiOKin.E 

 Not such flies 20 



20. Empodia developed pulvilliform, that ia, three nearly equal, 



membranous appendages on the under side of the claws. 21 



Empodia wanting, rmlimentary or linear, not developed like the 



pulvilli 23 



21. TegulcB very large, inflated ; thorax and abdomen inflated ; head ^ 



small, e3'es very large ; neuration varied. . Cjcbjid-e 



Tegulaj of moderate size or rudimentary. .... 22 



22. Middle tibia?, at least, with spurs, no bristles on femora or tibia? ; 



third longitudinal vein furcate; five posterior cells present 

 (four in Agnot omy ia); anterior cross-vein always distinct; 

 third joint of the antennae with a bristle or slender style, usu- 

 ally terminal LeptidvE 



Not such flies 23 



23. Third longitudinal vein of the wing simple, not furcate. . 32 

 Third longitudinal vein furcate, two or more submarginal cells 



present. .... ..... 24 



24. Arista or style of antennae, when present, always terminal. 25 

 Arista dorsal, always present. ... ... 3^ 



25. Vertex and front distinctly hollowed out transversely between 



the eyes; eyes of male never contiguous; basal cells large; 

 mostly large flies. ........ 26 



Front and vertex plane or convex ; eyes of male often con- 

 tiguous ..... 27 



26. Proboscis without fleshy labella at the tip, the under part form- 



ing a horny sheath ; the posterior branch of the third vein 

 terminates behind the tip of the wing; five posterior cells al- 

 ways present ; predaceous flies Asilid.e 



Proboscis with fleshy labella at the tip ; neuration complicated, 

 the third vein, at least, curves forward to terminate before 

 the tip of the wing; antenna? with a terminal flattened la- 

 mella. . MlDAID^ 



27. Five posterior cells in the wing ; basal cells large. . 30 

 Never more than four posterior cells in the wing. . . 28 



