FAMILY TACHIXID-12 — THE TACHIXIDS 433 



Face short, with a strong facial carina, the antennal grooves deep; 

 proboscis one-half longer than the head-height; abdomen without 

 bristles, the apical segments with longish hairs; female genitalia 

 with stout spines on the sides Imitomyia Townsend 



101. Second abdominal segment with at least well developed median mar- 



ginals 123 



Second abdominal segment without dorsal bristles 102 



102. Posterior tibiae without flattened bristles 108 



Posterior tibiae ciliate dorsally with scale-like bristles (163, 164). 



Trichiopoda Latreille 



103. Facial depression shallow or somewhat carinate, if deep not sub-oval 



in outline; arista, if wholly thickened, reddish in color 104 



Facial depression very deep and sub-oval; arista black, wholly thick- 

 ened; shining black flies (89) Melanophrys Williston 



104. Arista not wholly thickened; parafacials without transverse furrows. .105 

 Arista wholly thickened; parafacials shining black, with many trans- 

 verse furrows (25 ) Euscopolia Townsend 



105. Fourth vein strongly curved beyond the crossvein 106 



Fourth vein gently curved, the apical cell open in the wing-tip. 



Gyninophania Brauer & Bergenstamm 



106. Face not or but little retreating, the vibrissse situated well above the 



oral margin 109 



Face strongly retreating, oral vibrissae strongly differentiated and on 

 a level with the oral margin, or absent 107 



107. Apical cell petiolate 108 



Apical cell open near the wing-tip Pseudapinops Coquillett 



108. Apical cell ending well before the wing-tip. .. .*Hesperophasia Townsend 

 Apical cell ending in the wing-tip (55) Catharosia Rondani 



109. Oral vibrissae, if strongly differentiated, situated almost level with 



the oral margin; abdomen short, oval, spherical or flattened, rarely 



elongate 110 



Oral vibrissae sti'ongly developed, sometimes duplicated, situated well 

 above the oral margin and without hairs above or below; abdomen 

 long and narrow (71, 76) Xanthomelana Wulp 



110. Abdomen short, or if elongate not flattened Ill 



Abdomen elongate and flattened; oral margin produced; apical cell 



petiolate; wing veins broadly bordered with black. 



Bibiomima Brauer & Bergenstamm 



111. Sternites broad, the female genitalia not remarkably large; oral 



vibrissae usually strongly differentiated, their angle high above the 

 oi'al margin; abdomen short, rather spherical in outline, strongly 



convex or flattened 113 



Sternites linear, thread-like; second sternite large, produced down- 

 ward and with very short, stout setulse on the lower part; female 

 genitalia very large; vibrissae distinct, situated but little above the 

 oral margin; palpi minute 112 



* Curran, 1927, Can. Ent., lix, p. 300. 



