lin Noirni AMEiacAX dti'tetja. 



notuni bristly on tlie liind i)art only ; i)ropleural and stcrnoplcnral bristles 

 absent; female abdomen witli five seiimcnts; ovijjositor flattened; first 

 longitudinal vein bristly. 



1 . The picture of tlie wings consist chiefly of a dark border along the costa, 



from the base of the stigma to the tij) of the wing, with the first 

 l)asal cell and the posterior cross-vein clouded: anterior cross-vein 

 oblitjue. .... •......(■> 



Flies not having the above characters. ...... 2 



2. Posterior angle of the anal cell drawn out into a sharp point (Mexico). 



< )STi{.\coc(£r.TA (iiglio-Tos. 

 Posterior angle of the anal cell rounded. .....•'! 



0. Picture of the wings dark, varied with trans])arent spots and bars. 4 

 Wings not so marked. .........'> 



4. Scutellum large, flat; occiput but little swollen ; veins of wings straight 



and markedly divergent. .... Amphicnephes Loew. 



Scutellum smaller, not flattened; occiput much smaller; e})istonia 



strongly projecting; third and fourth longitudinal veins nearly 



parallel, sinuous (Mexico and South America). Platystoma Meigen. 



5. The picture of tiie wings consists of four blackish cross-bands, of which 



the third is nearly perjjendicular, and the fourth lies along the costa 

 at the apex of the wing; scutellum with four bristles. 



Uiv'ELLiA Desvoidy. 

 AVings without bands; scutellum with two bristles; ant-like flies. 



Myrmecomvia Desvoidy. 



li. Posterior cross-vein jirolonged beyond the fourth vein (Cuba). 



Ill.METiOKSSA I.oew. 



Posterior cross-vein not jirolonged. ...... > 



7. Fifth longitudinal vein bristly (Mexico). Hkuiniella (iiglio-'l'os. 



Fifth longituilinal vein not bristly.* . Stenopterin a Macquart. 



CEPHALIIN.K. 

 Oral opening very large; clypeus and jiroboscis greatly develojted; ])ro- 

 ])leural bristle absent; sternopleural bristle present; sixtii segment of the 

 abdomen in the female distinctly developeil ; ovipositor flattened: first 

 longitudinal vein bristly. 



1. Slender, Sepsis-like flies, resembling Myrnu-comyia, with wings almost 



hyaline, exce])t for a small infuscation at the stigma anil at the ti]i. 



('ei-hai.ia Meigi'H. 

 Wings with a cons])icuous j)icture. .....•- 



* 1 can not see wherein Bricinnia Walker, to wliich Giglio-Tos refers a 

 Mexican species, differs from Slniujifi-ritiK . 



