14 U.S. NATIONAL MUSEUM BULLETIN 277 



open distally; female 8th sternum longer than tergum, 9th tergum usually 



with short spines Brevicornis group (p. 93) 



Medium to small flies, short antennae, vein R4 branching beyond the middle 

 of cell R5; male 9th tergum 2-lobed closed below 



Velutinus group (p. 110) 



7. Vein R5 + M 1+2 ending at tip of wing 8 



Vein R5 + M1 + 2 bending sharply to end in leading edge 



Caenoneura Krober (p. 162) 



8. Long slender black flies 9 



Brown, tan or gray flies 11 



9. Head longer than high, body glabrous 10 



Head higher than long, mouthparts atrophied, hairy 



Belosta Hardy (p. 274) 



10. Ninth tergum of male about as long as high and as long as the 10th tergum. 



Female 9th tergum and sternum subequal, tip of cell R5 blunt 



Pseudatrichia Osten Sacken (p. 221) 

 Ninth tergum much taller than long, 10th tergum longer than 9th. Female 

 10th tergum with thick spines, tip of cell R5 sharp 



Neopseudatrichia, new genus (p. 299) 



11. Large robust bodied flies 12 



Smaller flies 13 



12. Very large flies with broad blunt abdomens in both sexes, frontal area swollen 



so that antennae project from middle of head; hairs often flat, scale-like 



Metatrichia Coquillett (p. 214) 



Smaller flies, with blunt abdomens, frons not swollen, male genitalia with 



flange-like lobes on inside of 9th tergum . . Paratrichia, new genus (p. 320) 



13. Small flies with pollinose scales on thorax 14 



Small flies, black, shining 17 



14. Wing with vein R4 branching from cell R5 near the base 15 



Wing with vein R4 branching from the cell R5 near the middle . . . .16 



15. Males with two long aedeagal spines, females with 8th sternum excavated on 



distal margin, 9th tergum often with row of stiff spines on posterior margin 



Brevitrichia Hardy (p. 165) 



Males with short aedeagal parameres, females with long pointed 8th sternum, 



9th tergum with stiff spines Heteromphrale Krober (p. 286) 



16. Males with 9th tergum as two flaps covering genitalia, females with spines on 



9th tergum Propebrevitrichia, new genus (p. 281) 



Males with 9th tergum as four long lobes, females without spines on 9th 

 tergum Riekiella Paramonov (in part) (p. 304) 



17. Antennae pointed, vein R4 branching from distal third of cell R5 



Stenomphrale Krober (p. 318) 

 Antennae blunt, vein R4 branching from before the middle of cell R5 



Pseudomphraie Krober (p. 164) 



Genus Scenopinus Latreille 



Omphrale Meigen, 1800, p. 29 (rejected name). 

 Scenopimis Latreille, 1802, p. 463. 

 Atrichia Schrank, 1803, p. 54. 

 Cona Schellenberg, 1803, p. 66. 

 Hypseleura Meigen, 1803, p. 273. 

 Scenopoeus Agassiz, 1846, p. 333. 



