70 DIPTERA OF NORTH AMERICA. [PART III. 



the slender arista is distinctly pubescent j the abdomen is of an 

 equal breadth ; the posterior angle of the anal cell is not acute 

 and the fourth longitudinal vein somewhat convergent with the 

 third ; all the femora are armed. 



I have also to mention the genus Coniceps, which I find 

 necessary to establish for a North American species. On account 

 of the retracted posterior angle of the anal cell it must likewise 

 be placed among the Richardina, although in its general appear- 

 ance it is more like certain Ulidina, especially Eumetopia. 



The reason why I place Epiplatea among the Richardina has 

 been alluded to above. 



Thus I have reached the limit of the genera, the location of 

 which among the Richardina appears to me beyond doubt. It 

 is certain that the number of Richai^dina which may yet remain 

 unrecognized among the existing descriptions is far from ex- 

 hausted by me ; but who would venture, upon the statements of 

 most of these descriptions, to form an opinion on ihe systematic 

 location of the species which they mean to represent ! 



It will hardly be necessary to mention here the East Indian 

 genus Meracantha. Its spinose femora may suggest the sup- 

 position that it belongs to the Richardina. But as this character 

 does not belong exclusively to this group, and as the very acute 

 angle of the anal cell of Meracantha does not occur among the 

 Richardina in the acceptation of that group as I understand it 

 here, I cannot consider Meracantha as belonging to the 

 Richardina. 



Besides the bareness of the first longitudinal vein and the not 

 acute posterior angle of the anal cell, which two characters con- 

 stitute the diagnosis of the Richardina, the following characters 

 are common to all the genera which I have had occasion to ex- 

 amine in detail: a break in the costal vein immediately before 

 the end of the auxiliary vein; the great proximity between the 

 auxiliary and first longitudinal veins and the very small distance 

 between their ends ; finally the thoracic dorsum being beset with 

 bristles upon its posterior part only. 



