FAJIILY CONOPID.E — THE THICK-HEADED FLIES 267 



3. Anterior crossvein situated at most a little beyond the middle of the 



discal cell ; femora regular in outline ^ 



Anterior crossvein situated well beyond the middle of the discal cell; 

 femoi'a swollen basally, narrowed on the apical half or more (2). 



' Physocephala Schiner 



4. Proboscis geniculate 5 



Proboscis straight, directed forward (3) Zodion Latreille 



5. Vertex and tibiae without bristles; face grooved 6 



Vertex and the apex of the tibiae with bristles; face not grooved (8). 



tStylogaster Mac()uart 



6. Anal cell much longer than the second basal 7 



Anal cell but little longer than the second basal (7). .Dalmannia Desvoidy 



7. Cheeks narrower than the eye-height 8 



Cheeks at least as wide as the eye-height (6) Myopa Fabricius 



8. Antennae longer than the front; propleura haired (5). . .Occemya Desvoidy 

 Antennae shorter than the front; propleura bare Sicus Scopoli 



9. Third antennal segment much longer than either the first or second. 



Aconops Krceber 

 Third antennal segment at most slightly longer than the first or 

 second ( 1 ) JConops Linnaeus 



* Van Duzee. 1934, Ann. Ent. Soc. Amer.. xxvii, p. 320. 

 t Aldrich, 1930, Proc. U. S. N. M., Ixxviii. Art. 9, pp. 1-27. 

 I Krober, 1927, Konowia, vi, p. 139. 



