110 NORTH AMERICAN DIPTERA. 



TABLE OF GENERA. 



1. Second joint of the antennas with a short spinous bristle at tlie anterior 



upper end. ........... 2 



Second joint of antennse without a spinous bristle at the anterior end. 8 



2. The costal vein reaches to the tip of the third longitudinal vein. 3 

 The costal vein reaches to the tip of the fourth longitudinal vein. 4 



3. Tip of the abdomen in the male with elongated bristles. 



UicniETA Meigen. 

 Tip of the abdomen in the male witliout elongated bristles. 



NoTiPHiLA Fallen. 



4. Abdomen broad. ...... Discomyza Meigen. 



Abdomen not broad. ......... 5 



5. Face on the upper part flat or gently convex, not carinate ; third joint 



of the antennaj oval. ...... Psilopa Fallen. 



Face distinctly carinated above. ....... 



6. Cheeks narrow ; eyes long. .... Clasiopa Stenhammer. 

 Cheeks broad, eyes round. ........ 7 



7. Clypeus prominent A%thyroglos.sa Locw. 



Clypeus projecting but little beyond the oral margin. 



Hecamedk Ilalliday. 



8. Middle tibia? witli several long bristles exteriorly. Paralimna Locw. 

 Middle tibia; without long bristles exteriorly. .... 9 



9. Oral opening small; eyes usually pubescent (//y^//r///nrr). . . 10 

 Oral opening large {Epht/drhm'). . ... - . .10 



10. Front femora thickened. . . . . . . .11 



Front femora not thickened. ....... 12 



11. Front femora much thickened; first posterior cell narrowed at the bor- 



der of the wing. ...... Octhera Latreille. 



Front femora moderately thickened ; third and fourth veins parallel 

 (West Indies). ..... Ochtheroidea Williston. 



12. Eyes thickly but short pubescent. Hydrellia Desvoidy. 

 Eyes sparsely pubescent or bare. ....... 13 



13. Sides of the face wholly without bristles. . Hvadina Ilalliday. 

 Sides of the face with bristles. . 14 



14. Eyes wholly bare. ...... . . .15 



Eyes sparsely pubescent; clypeus hiilden. Piiiliivgria Stenhammer. 



1.5. Clypeus projecting; anterior part of mcsonotum without bristles. 



Pelina Ilalliday. 

 Clypeus hidden; anterior part of the mcsonotum with bristles. 



Pelomvia Williston. 



