160 NORTH AMERICAN DIPTERA 



5. Third antennal segment round, oval or conical 7 



Third antennal segment kidney-shaped, with dorsal or subdorsal arista. 6 



6. Posterior tibiae with two teiTninal spurs (8, 13) Atherix Meigea 



Posterior tibiae with one terminal spur (4, 12). .Symphoromyia Fi*auenfeld 



7. Posterior tibiae with one terminal spur 8 



Posterior tibiae with two terminal spurs (2, 10) Rhagio Fabricius 



8. Antennae bearing a terminal style 9 



Antennae with a long, slender terminal arista which is decidedly longer 



than the basal three segments combined (6, 15) . .*Chrysopilus Macquart 



9. Style situated near the middle of the third antennal segment (5, 9). 



fPtiolina Zetterstedt 

 Style situated at the lower end of the third antennal segment. 



Spania Meigen. 



* Curran, 1931, Amer. Mus. Novit. No. 462 (Tropical). 

 t Curran, 1931, Can. Ent., Ixiii, p. 249. 



