24 Families and Genera of 



jecting, never elongate, without terminal fleshy labella, adapted for 

 piercing. Abdomen with eight segments, the hypopygium or ovi- 

 duct usually prominent. Legs strong, moderately long; empodia 

 bristly, not pulvilliforni, the pulvilli sometimes rudimentary. Basal 

 cells of the wing long ; five posterior cells, two or three submarginal 

 cells ; anal cell open or closed in the margin. 



The flies are usually observed in sunny open paths, or upon leaves 

 of underbrush, on the alert for other insects, which they seize upon 

 the wing and pierce with their stout proboscis. 



1. Marginal cell of the wing open. (Dasypogonina;.) . 2 

 Marginal cell closed. 33 



2. Front tibiae with a terminal claw-like spur. ... 28 

 Front tibial without terminal claw-like spur 3 



3. Pulvilli rudimentary or wanting 4 



Pulvilli normal. 5 



4. Face very narrow ; abdomen very long, slender, narrow on prox- 



imal part ; hind legs elongate, slender. . Leptogaster 



Face moderately narrow ; abdomen not unusually long, broader 



at base; hind legs not elongate. . . . Ablautatds 



5. Head narrow, about as high as broad; face narrow above, broader 



and swollen below, in large part covered with hair. Large, 

 elongate species. ........ 6 



Head very obviously broader than high. . ... 8 



H. Antennae with a terminal style 7 



Third joint of antennae very long, without style; fourth posterior 

 cell closed before the border of the wing. Black species with 

 or without red on the abdomen. . . Ospriocekus 



7. First posterior cell open, not closed before the border of the 



wing. Stenopogon 



First and fourth posterior cells closed before the border of the 

 wing ; third joint of antennie shorter, style longer. 



Scleropogon 



8. Fourth posterior cell closed before the border. ... 9 

 Fourth posterior cell wide open, rarely nearly closed. 13 



9. Antenna} elongate, of five joints (Myelaphus). 14 

 Antennae not elongate, of three joints, and a terminal style. 10 



10. Face bare, except on oral margin ; abdomen elongate, cylindro- 

 idal ; anterior intercalary vein continuous, or nearly so, with 



