420 NORTH AMERICAN DIPTERA 



E. Eyes bare or with inconspicuous short hair G 



Eyes pilose ^ 



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



Parafacials bare at least on the low^er half 181 



G. Parafacials with hairs or bristles 23'i 



Parafacials bare on at least the lower half H 



H. Thorax without plumose hairs I 



Thorax with plumose hairs Teleothyria 



I. Facial ridges bristled on less than the lower half J 



Facial ridges with strong bristles on lower half or more 293 



J. Apical crossvein present ". 



Apical crossvein absent 342 



K. Palpi present and well developed I' 



Palpi absent or very greatly reduced 348 



L. Apical cell at most with an extremely short petiole M 



Apical cell long petiolate 355 



M. Ultimate section of fifth vein less than half as long as the preceding 



section 



Ultimate section of fifth vein three-fourths as long as the preceding 

 section Catalinovoria 



N. Penultimate aristal segment not over twice as long as wide O 



Penultimate aristal segment three times as long as wide 361 



0. No appendage or strong fold at bend of fourth vein 385 



A strong appendage or fold at bend of fourth vein 372 



KEY TO GENERA 



1. Lower lobe of squamae bare or pubescent above 3 



Lower lobe of squamae with long, fine hairs above 2 



2. Parafacials haired to below the middle (113) Bombyliopsis Townsend 



Parafacials with but a few hairs below the frontals (91). 



Hystricia Macquart 



3. Middle of propleura bare 53 



Middle of propleura with pile or hair 4 



4. Eyes thickly hairy, the head almost as long below as at base of 



antennae '■ ^ 



Eyes bare, or, if pilose, the face retreating and the facial ridges usu- 

 ally bristled on the lower half 8 



5. Parafacials bare " 



Parafacials haired on lower half ' 



6. Facial ridges bristled on lowest three-fourths; first vein setulose. 



Hypochaeta Brauer & Bergenstamm 

 Facial ridges and first vein bare (100). 



Pseudohystricia Brauer & Bergenstamm 



