208 DIPTERA OP NORTH AMERICA. [PART II. 



rubbed off; the other parts of the pleurae are dusted with gray. 

 The scutellum, which has two bristles, is greenish bronze-colored 

 and opaque. The very shining abdomen is of a bright coppery 

 color, but assumes, when its surface is looked upon in a very ob- 

 lique direction, a green or at least brassy -yellow color. The tape- 

 like anal appendages are very long, somewhat blackened at the 

 basis, and still more so at the tip which is turned upwards, and 

 there beset with a small tuft of blackish hair directed backwards ; 

 otherwise their margins are not hairy, although there is a single 

 black bristle where the blackening of the tip begins on the under 

 side in the vicinity of its inner margin. Near the anus between 

 the above mentioned two appendages there are a few small black 

 hairs. Coxae greenish-black, with white-yellowish dust ; the fore- 

 most have besides some pale hairs, almost imperceptible on account 

 of their shortness and delicacy, a few black bristles before and upon 

 the tip. Feet black with a metallic-green reflection, which gra- 

 dually disappears upon the last joints of the tarsi. Fore femora 

 towards their root not so much thickened as in the two preceding 

 species, beset with strong black bristles of different length on the 

 under side, on the front side with a sparse row of short black bris- 

 tles. Middle and hind femora long, slender, straight, of a plain 

 structure, beset on the second half with a moderate number of 

 short, scattered black bristles. The moderately stout fore tibias 

 bear on their anterior side, not far from the basis, a short black 

 thorn and are prolonged at their tip into a large, somewhat clumsy 

 but sharp tooth, before which the under side of the tibia, provided 

 with bristles, has a very small excision. The middle tibiae are 

 long and slender ; on the upper side they are beset with only three, 

 on the anterior side with about seven scattered bristles of very 

 moderate length ; on the other half of their hind side they bear 

 long curly black hairs. Hind tibiae slender, straight, rather long, 

 only on the second half with a few isolated black bristles ; the 

 bristles on the outside of their tip are also only short. Tarsi 

 plain, their joints of decreasing length ; the first joint of the fore 

 and middle tarsi on the under side with numerous black bristles, 

 the first joint of the hind tarsi only with a few and much shorter 

 bristles. Wings hyaline-gray, somewhat darker towards the tip 

 on account of the gray margin of the second, third and fourth 

 longitudinal veins ; upon the posterior transverse vein and upon 



