52 DIPTERA OF NORTH AMERICA. [PART II. 



margin, as in the resembling species, but also upon the greater 

 part of the upper side. Lamellae of the hypopygiuru of ordinary 

 size, rounded-ovate, on the upper and apical margin narrowly bor- 

 dered with black, the latter jagged and fringed with black bristles. 

 Fore coxa3 yellowish- white, and except some black bristles near 

 their tip, beset with only very delicate minute whitish hairs. Mid- 

 dle and hind coxae of the same color, the former darker only at the 

 basis. Hind femora before the tip with a black bristle, upon the 

 under side ciliated with about 6 to *7 yellowish hairs ; hind tibiae 

 rather stout, but not thickened ; in very dark colored specimens 

 sometimes near the tip and also upon the fore and hind side with 

 a little brown blot; upon their hind side only a short glabrous 

 stripe, which does not reach to their middle; fore tarsi slender, 

 plain, about 1^ times the length of the tibiae ; only their last joint 

 black. Middle tarsi from the tip of the first joint brownish, to- 

 wards the end blackish-brown, in paler specimens generally but 

 moderately brownish. Hind tarsi generally entirely black, some- 

 times paler towards the end of the first joint or also at the end 

 of the second joint ; in the palest specimens brownish only towards 

 the end. Cilia of the tegulae yellowish. "Wings rather dis- 

 tinctly clayish-yellow ; veins clayish-yellow ; the fourth longitudi- 

 val vein not broken ; the costa near the tip of the first longitudi- 

 nal vein with a little swelling. 



Hob. Washington. (Osten-Sacken.) 



Observation. — With regard to a female which may be taken 

 for that of the present species, the necessary remarks have been 

 made in the observation to the previous species. However un- 

 usual the inconstancy in the coloring of the tarsi of D. luteipennis 

 and of D. variabilis may be, I have no doubt that these varieties 

 do not represent different species. At least the most attentive ex- 

 amination of the specimens distinguished by the coloring of their 

 feet, did not lead to the discovery of the slightest difference in 

 the plastic characters in one as well as in the other species. 



b. Cilia of the tegulae black. 



1. Fourth longitudinal vein broken. 



a. Antennae black. 



23. D. i a m i fer Loew. % and 9 • — Obscure viridi-aeneus, thoracis 

 dorso aeneo-nigro, facie alba, antennis nigris, ciliis oculoruiu inferioribus 



