446 NORTH AMERICAN DIPTERA 



226. Head as long below as at the antennae; antennae arising below the 



middle of the eyes Tricogena Rondani 



Head shorter below than at antennae; abdomen flattened. 



*Nemorilla Desvoidy 



227. Vibrissae situated at most slightly above the oral margin 229 



Vibrissae situated more than half the length of the second antennal 



segment above the oral margin 22S 



228. Abdomen with strong discals. . .fMacromeigenia Brauer & Bergenstamm 

 Abdomen without discals on the intermediate segments. 



Bolomyia Brauer & Bergenstamm 



229. Apical abdominal segment closing slit-like, deeper than wide 230 



Apical abdominal segment not closing slit-like, wider than deep at the 



base 231 



230. Several coarse setulse below the frontals; facial depression very deep; 



parafacials as wide as the facial depression. . .Organomyia Townsend 

 No hairs below the frontals; parafacials not over half as wide as 

 the shallower facial depression Leptostylum Macquart 



231. Anterior tibiae with at least two posterior bristles 232 



Anterior tibiae with a single posterior bristle 233 



232. Third antennal segment more than twice as long as wide (57, 94). 



JZenillia Desvoidy 



Third antennal segment subtriangular, almost as wide as long. 



Obolocera Townsend 



233. Discals absent; abdomen broad; cheeks linear (171, 182). 



Anadiscalia, n. g. 

 Discals present; cheeks at least one-fifth the eye-height 234 



234. Frontal vitta of male very narrow; female with stout spines on the 



apex of the middle coxae; abdomen broad (136, 137, 153, 175). 



Doryphorophaga Townsend 

 Frontal vitta not unusually narrow; female without spines on middle 

 coxae Ptilodegeeria Brauer & Bergenstamm 



235. Parafacials with hair or bristles on the lower half 236 



Parafacials bare on the lower half 291 



236. Ocellar bristles present, directed obliquely forward or divergent 248 



Ocellar bristles directed obliquely backward, absent or hair-like 237 



237. Ocellars directed obliquely backward 238 



Ocellars hair-like or absent 240 



238. Facial ridges with strong bristles on the lower half, or the penulti- 



mate aristal segment not over twice as long as wide; head not 



strongly inflated in appearance 239 



Facial ridges bristled on less than the lowest fourth, the head inflated 

 in appearance; penultimate aristal segment always more than three 

 times as long as wide (12, 13) Gonia Meigen 



* Aldrich & Webber, 1924, Pr. U. S. N. M., Ixiii, Art. 17, p. 5. 



t Reinhard, 1930, Ent. News, xli, p. 262. 



J Aldrich & Webber, 1924, Pr. U. S. N. M., Ixiii, Art. 17. p. 11. 



