MUSCIDEA— BOKBORIDiE. 101 



27. Anal cell wholly wanting; face usually large ami arched, with the 



mouth opening large Epiiydkid.k. j Y 



Face not arched, and tlie mouth opening never remarkably large. 28 



28. Arista loosely and long plumose Drosophilid.e. \ O / 



Arista not plumose, or wanting. .... Kgkouwad.v.. j Oh^ 



20. Scutellum elongate, triangular, with protuberances or spines on its mar- 

 gin ; femora thickened Riioi'ALOMeuid/E. / 2^7 



Flies without both the above characters. ..... :]0 



oO. Oral vibrissa present 31 



Oral vibrissas wanting. ........ 35 



31. Front bare or bristly at the vertex only {Pinpliilimr). . ^nvsiDAi. j ( f 

 Front bristly at least as far as the middle 32 



32. Posterior cross-vein situated before tlie middle of the wing, the two 



cross-veins approximated. ..... Agromyzii>.k. ( iP'^ 



Posterior cross-veins situated beyond the middle of the wing, the two 

 cross-veins not much approximated. ..... 33 



33. Arista bare; body short and broad (il///iV///7j«). . Agromyzid^. /^^ 

 Arista pubescent or plumose, or, if bare, the abdomen elongate. 34 



34. Arista with a few long hairs, mostly on the upper side. DROSOi'HiLiDiic. / I 

 Arista thickly short plumose, pubescent or bare. . CiEOMYziPiE. /{y*^ 



35. Posterior basal and the anal cell of considerable size, distinct. . 3(i 

 Posterior basal and the anal cell small and indistinct. . . 37 



36. Front bristly on the sides Trypetid.'e. / '^ . 



Front bristly at tiie vertex only, or bare. .... Psilidte. { \'f 



37. Silvery white or whitish gray species, with unspotted wings; third 



antennal joint usually angulated on the upper angle. Agromyzid^. I 7, 

 Reddish yellow or brownish red species, often with spotted wings ; 



third antennal joint rounded at the tip. . . Geomyzid^5. I ^ 



.33. BORBORID^. 



Moderately large to small, black, brown or obscurely yel- 

 lowisli flies, having a qnick, short flight. Head hemispherical ; 

 face obtusely carinate in the middle ; vibrissae present ; front 

 broad, usually bristly. Antennae short ; third joint rounded, 

 the arista bare or pubescent. Second segment of the abdomen 

 with a transverse depression ; genitalia sometimes moderately 



