CLASSIFICATION OF INSECTS 327 



N. Auxiliary vein absent or in- 

 complete ; first vein usually 

 ends in the costa before the 

 middle of the wing; head 

 produced on each side into 

 a lateral process for the 

 eyes . . '> DIOPSIDAE 



NN. Hind metatarsi incrassated 

 and usually shorter than the 

 second joint ; oral vibrissae 

 present. Small flies about 

 excrement near water. 



BORBORIDAE 



O. Discal and basal cells 

 united, anal cell absent; 

 front bare or at most 

 bristly above. Small, 

 usually light-colored 

 flies . . OSCINIDAE 

 OO. Front often bristly, 

 face often very convex, 

 mouth cavity usually 

 large ; no oral vibrissae. 

 Small dark-colored flies 

 about water. 



EPHYDRIDAE 

 P. Anal cell complete 

 oral vibrissae pres- 

 ent ; aristae long, plu- 

 mose, or pectinate 

 above. Vinegar or 

 pomace flies. 



DROSPHILIDAE 

 PP. Arista bare or pubes- 

 cent ; front bristly 

 at least as far as 

 the middle. Very 

 small flies, compris- 

 ing most of the leaf- 

 miners. 



AGROMYZIDAE 

 Q. Oral vibrissae ab- 

 sent ; anal cell an- 

 gular; no preapi- 

 cal tibial bristle; 



