364 NORTH AMERICAN DIPTERA 



3. Ciniciate interfrontals arising from the orbits (9, 14) . . . .Czernyola Bezzi 

 Cruciate interfrontals arising on the fi'ontal vitta (1, 4, 7). 



Clusioides Coquillett 



4. Cruciate interfrontals absent 5 



Cruciate interfi'ontals present (5, 10) Clusia Haliday 



5. First vein with dorsal setae; postverticals absent (2, 6). 



Chaetoclusia Coquillett 

 First vein bare; postverticals pi'esent 6 



6. Preapical bristles on middle tibise and prescutellar acrostical bristles 



present; presutural dorsocentrals absent (12, 13) . .Sobarocephala Czerny 

 Preapicals and prescutellar acrosticals absent (3) . .Heteromeringia Czeray 



