FAMILY TACHIXID.E THE TACHIXIDS 437 



127. Pteropleural bristle normal 128 



Pteropleural bristle reaching to the apex of the squamse. 



Meleterus Aldrich 



128. Face retreating- below Paedarium Aldrich 



Face as long below as at the antennae Chaetovoria Villeneuve 



129. Oral vibrissse situated level with the oral margin; posterior crossvein 



situated near the middle of the wing 180 



Oral vibrissEe either situated well above the oral margin or the pos- 

 terior crossvein near the apical third of the wing 133 



130. Cheeks very much narrower than the eye-height 131 



Cheeks almost or quite as wide as the eye-height... .*Uclesia Girschner 



131. Facial depression broad and shallow, the edges rather flattened 132 



Facial depression deep and narrow, the edges prominent. 



Menetus Aldrich 



132. Parafacials rather narrow, with small hairs over a considerable part 



of the surface Metavoria Townsend 



Parafacials wide Metaplagia Coquillett 



133. Apical cell at most extremely short petiolate 134 



Apical cell long petiolate 137 



134. Face strongly receding below; third antennal segment about three 



times as long as the second; three pairs of strong scutellars, the 



apical pair widely spaced and divergent 13G 



Face usually but little receding; third antennal segment less than twice 

 as long as the second 135 



135. Costal spine short; facial depression rather narrow (35, 139). 



Myiophasia Townsend 

 Costal spine long and strong; facial depression wide Lasionalia, n. g. 



136. First vein setulose on apical half Meigeniella Coquillett 



First vein bare (34) fCryptomeigenia Brauer & Bergenstamm 



137. Third vein ending near the wing-tip (32, 33) Rhinophora Desvoidy 



Third vein ending far before the wing-tip Steveniopsis Townsend 



138. Frontal vitta opaque 139 



Frontal vitta shining black (37, 38) Hemyda Desvoidy 



139. Posterior tibiae without scale-like bristles 140 



Posterior tibiae ciliate above with scale-like bristles (102, 139). 



Trichiopoda Latreille 



140. Anterior femora with a row of long bristles on at least the apical 



half of the posteroventral surface, appearing as widely spaced cilia. 141 

 Anterior femora with at most two or three posteroventral bristles 

 apically; the hairs on the posterior sui-face wholly appressed (18, 

 19) Acaulona Wulp 



141. Apical cell open, or if closed in the wing margin there are hairs about 



the base of the vibrissas 143 



Apical cell closed and petiolate 142 



* Curran, 1927, Can. Ent.. p. 299. 



t Curran, 1926, Tr. Roy. Soc. Canada, Sec. v, p. 156. 



