SCIOMYZID^. 



323 



TABLE OF GENERA. 



1. Second joint, at least, of antennae short. .... 2 

 Antennae elongated. ......... 



2. Face excavated, the oral margin protuberant. .... 4 

 Face retreating in profile, but little or not at all excavated; oral 



margin but little or not at all prominent. .... 3 



3. Head strongly projecting forward (9). . Trigonometopus. 

 Head not at all projecting (7). .... Sciomyza. 



4. Cheeks broader than the long diameter of the eyes; oral border 



moderately protuberant; costa somewhat spinose. Actora.* 



Cheeks not broader than the long diameter of the eyes; oral margin 



very prominent; costa bare. ...... 5 



5. Clypeus prominent. ......... 6 



Clypeus not prominent. ........ 7 



6. Scutellum with four bristles on its border. . Neuroctena. 

 Scutellum with six bristles (p. 80, 17, 18). . Heterocheila. 



7. Front tibiae with a preapical bristle. . . . Bischofia. 

 Front tibiae without preapical bristle. . . . Dryomyza. 



8. Hind femora long; second antennal joint much elongated, longer 



than the third. ......... 9 



Hitid femora only moderately elongated and but little thickened; 

 second antennal joint as long or a little shorter than the third 

 (5) Tetanocera. 



9. Hind femora thickened; face not produced downward (1, 2, 3). 



Sepedon. 

 Hind femora not thickened; face much produced downward (8). 



Thecomyia. 



* Of doubtful occurrence in North America. 



