104 XORTII AMERICAN DIPTERA. 



o. Second basal cell as long or but littk' shorter than tlie first. ,''; 



PnYT OiMYZA F; iJ.lei| [ j ' • ' C ^ 



Second basal cell distinctly shorter than tlie first ( ^1 (jromi/zinoi) . "N. 4 ^.^.^ 



4. First posterior cell narrowed at tiie margin. . Leiomyza MeigcnV ^^p^^ 

 First posterior cell not narrowed at the margin, the third and fourth \.,^^_^^ , 



longitudinal veins nearly parallel 5 ----X 



5. Third antennal joint terminating in a spiny point. 



Ceratomyza Schiner. 

 Third antennal joint does not terminate in a spiny point. . . (> 



0. Third antennal joint rounded, of moderate size.* Agromyza Fallen. 

 Third antennal joint very large, subquadrate in shaiie. 



PuYLLOMVZA Fallen. 



7. Second basal cell united with the discal cell 8 



Second basal cell separated from the discal cell by a small cross-vein. 9 



8. Arista wholly wanting Cktptoch.etum Rondani. 



Arista present, bare; cross-veins remote, the anterior one situated near 



the base of the wing. . . . Aulacigaster Macquart. 



9. Oral vibrissic present; abdomen short and broad {Milichina). 10 

 Oral vibrissa; wanting; the abdomen elongate oval {Oditliipliilimi). VI 



10. Costa with a deep incision before the tip of the first vein. 



yiUiUei^x.'^-^ T.ORWPTK.itA Wahlb erg. 

 Costa not with sucb an incision 11 



11. Eyes round; mesonotum with bristles in the middle. M iijIOiii A -^ei gen . 

 Eyes oval ; mesonotum with bristles on the sides only. t-'^K^»-«-«'^_ 



Cacoxenus Loew. 



12. Front with long bristles on the sides. . . Ochthiphila Meigcn. 

 Front without bristles on the sides. . . . Leucopis Meigen. 



35. GEOMYZID^. 

 Head rounded; face usually with vibrissa^; front broad, 

 bristly below the vertex. Antennae sliort, the third joint 

 round or a little elongated, with a bare, pubescent or plumose 

 arista. Wings comparatively long; auxiliary vein rudimen- 

 tary ; posterior basal cell and the anal cell present. 



* Tlie genus Desmometopa Loew has never been described, but will bo 

 included in Agroiujisn ; I do not know it. 



