FAMILY TACHIXID.T: THE TACHIXIDS 44] 



152. Proboscis very long and slender; ovipositor normal. Ginglimyia Townsend 

 Proboscis short, the labell« fleshy; ovipositor as long- as abdomen. 



Xiphomyia Townsend 



153. Ocellars distinct 155 



Ocellars absent; three sternopleurals 154 



154. Abdomen broad, oval as in Sturmia ProrogluU Townsend 



Abdomen rather narrow, tapering Lixinia Curran 



155. Vibrissce situated above the oral margin, the oral margin not promi- 



nent (108) Viviania Rondani 



Vibrissse practically level with the oral margin, the oral margin slightly 

 produced 156 



156. Two or three pairs of presutural acrosticals, the middle pair always 



strong . 157 



One or two pairs of weak presutural acrosticals. Ochromeigenia Townsend 



157. First vein bare 15S 



First vein setulose Thelairochaetona Townsend 



158. Anterior tibi£e with a single posterior bristle Erycioides Curran 



Anterior tibiae with two posterior bristles (Lydella auct.) (135, 192). 



*Blondelia Desvoidy 



159. Eyes with long or dense hair 160 



Eyes bare or with inconspicuous, short spai'se hair 235 



160. Parafacials with hairs or bristles extending to the lower half 161 



Parafacials with at most a few hairs below the frontals 181 



161. Palpi normal in length, usually thickened apically 162 



Palpi greatly reduced, slender, never much more than twice the length 



of the thickness of proboscis at point of attachment; bend of fourth 

 vein with long appendage (77) Linnaemya Desvoidy 



162. Frontal bristles not extending below the upper third of the face, nor- 



mally only one situated below the base of the third antennal seg- 

 ment, the parafacials with other hairs or bristles at least above. . . .163 

 Frontals extending to the middle of the third antennal segment; 

 pteropleural reaching to the apex of the squamse Lypha Desvoidy 



163. Facial ridges not bristled on more than the lowest fourth or the 



ocellars proclinate 165 



Facial ridges bristled on at least the lower half; ocellars absent or 

 reclinate 164 



164. Ocellars absent Tritaxys Macquart 



Ocellai-s reclinate Distichona Wulp 



165. Penultimate aristal segment rarely twice as long as wide, the preced- 



ing segment always short 166 



Basal two aristal segments greatly elongate Digonichaeta Rondani 



166. Abdomen with strong discals 173 



Abdomen without strong discals 167 



167. Apical cell long petiolate 168 



Apical cell open 169 



* Curran, 1927, Can. Ent. lix, p. 12 (Lydella). 



