124 NORTH AMERICAN DIPTERA. 



2. Metallic black species ; front narrow. . . . LOXCH.*:A Fallen. 

 Yellow or yellowish species; front broad. . . PALLOPTERA Fallen. 



3. Arista with a short, dense plumosity; face with a strong gibbosity in 



the middle. . ... . . . PACHYCERINA Macquart. 



Arista slender, bare, pubescent or plumose, not having an appearance 

 of solidity. 4 



4. Face very broad, in profile strongly convex below. 



PHYSOGENIA Mac-quart. 

 Face receding, flattened or gently arched 5 



5. First posterior cell much narrowed in the margin (Central and South 



America). . . . . . . GRIPHONEUKA Schiner. 



First posterior cell not or but slightly narrowed in the margin. . 6 



6. Shining black species ; third joint of antennas more or less elongate. 



LAUXANIA Fallen. 



More or less yellow species ; third joint of antennae not more than three 

 times as long as wide SAPROMYZA Fallen. 



46. RHOPALOMERIM:. 



Front broad, excavated, with or without short bristles. 

 Antennae short, third joint rounded or oval, the arista bare or 

 plumose. Face broad, carinate, tuberculate or the oral margin 

 prominent; cheeks broad; clypeus projecting; vibrissae want- 

 ing ; proboscis short ; palpi slender or dilated. Thorax elon- 

 gate, arched, mesonotum nearly bare; scutellum often promi- 

 nent and grooved. Abdomen shorter than the wings, flattened; 

 ovipositor projecting, telescopic; hypopygium largely con- 

 cealed. Femora thickened, the hind tibiae often dilated. 

 Auxiliary vein present or absent ; basal cells well developed. 



This group comprises a small number of flies from six 

 to twelve millimeters in length, of peculiar aspect, having a 

 general resemblance to some of the Ephydridae or Ortalidae. 

 I know nothing of their habits, whether in the adult or imma- 

 ture stages, though I suspect that they are denizens of wet or 



No mention is made of tibial bristles, and the author is in some doubt 

 whether or not-it should be located with the Trij}>etid(i>. 



