124 NORTH AMERICAN DIPTERA. 



2. Metallic black species ; front narrow. . . . Lonch^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. ...... Pachycekina Macquart. 



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

 of solidity. 4 



4. Face very broad in profile strongly convex below. 



Physogenia Macquart. 

 Face receding, flattened or gently arched 5 



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



America). Griphoneuka Schiner. 



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



G. Shining black species; third joint of antenna; more or less elongate. 



Lauxania Fallen. 



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



times as long as wide • Sapromyza Fallen. 



46. RHOPALOMERID.E. 



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; vibrissse 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 tibia? 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 sus})ect 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 hv located with tlie Trii]>etldit'. 



