ASILIDJE. 57 



28. Face bare with bristles on the oral margin, in profile straight or con- 



cave, the oral margin most prominent 29 



Face convex below, the oral margin not prominent, more or less cov- 

 ered with hair. . . . . . . . . 31 



29. Fourth posterior cell closed a considerable distance before the margin 



of the wing. . . . . . ' f . . . .30 



Fourth posterior cell open or closed in the margin. SARAPOGON Loew. 



30. Hind pulvilli much shorter than the elongated claws; abdomen con- 



tracted toward the base (Central and South America). 



BLEPHAREPIUM Rondani. 



Hind pulvilli not much shorter than the claws ; abdomen not contracted 

 toward the base. . . . . DEROMYIA Philippi. 



31. Third joint of the antennas more or less dilated, the style very short. 



LESTOMYIA Williston. 

 Third joint of antennae slender, elongate 32 



32. Head broad and flat, the face not gibbose 33 



Face convex, densely covered with hair; thickly pilose species (Cen- 

 tral and South America). .... LASTAURUS Loew. 



33. Abdomen finely punctulate TARACTICUS Loew. 



Abdomen smooth, not punctulate. .... . . .34 



34. Hind tibiae at the tip and their tarsi thickened 35 



Hind tibiae at the tip and their tarsi not thickened ; fourth posterior 



cell wide open (Mexico). . . . COPHURA Osten Sacken. 



35. Fourth posterior cell wide open ; abdomen flattened, in the 9 a little 



broader beyond the middle; in the $ near the tip, the last two seg- 

 ments of which are conspicuously silvery above. 



NICOCLES Jaennicke. 



Fourth posterior cell narrowed ; abdomen of male not silvery above 

 (Blacodes preoc.) . . . . . LOEWIELLA, nom. nov. 



LAPHRIN.&:. 



1. Front tibiae with a terminal claw-like spur 2 



Front tibiae without claw-like spur 4 



2. Hind tibiae thickened, club-like at the extremity ; hind metatarsi thick- 



ened and elongate. 3 



Hind tibiae not clubbed ; hind metatarsi of the usual structure (Central 

 and South America). .... MEG APOD A Macquart. 



3. Thorax projecting prominently in front over the head (Central and 



South America) PSEUDORUS Walker. 



Thorax not projecting prominently in front (Central and S. America). 



DORYCLUS Jaennicke. 

 7 



