182 DIPTERA OF NORTH AMERICA. [PART II. 



b. Costa of the male not thickened. 



9. C. discolor Loew. % and 9 . — Viridis, nitens, femoribus concolori- 

 bus, genibus, tibiis venisque alarum flavis, maris oculis distantibus et 

 abdomine violaceo. 



Shining green, also the femora ; knees, tibise and veins of the wings yel- 

 low ; eyes of the male separated and its abdomen violet. Long. corp. 

 0.09—0.10. Long. al. 0.10—0.11. 



Syn. Chrysotus discolor Loew, Neue Beitr. VIII, 65, 6. 



Male. Shining green. The face rather broad for a male, a 

 little narrower towards the bottom, with yellow-grayish or rather 

 white-grayish dust upon green ground. Palpi rather small, black. 

 The third joint of the antennae not very large with an apical arista. 

 Front with rather thick brownish-yellow dust upon green ground. 

 The upper side of the thorax and the scutellum bright golden- 

 green, the posterior end of the former "and the latter sometimes 

 more blue-green. The brownish-yellow dust on the upper side of 

 the thorax is distinct, but not sufficient to conceal the ground- 

 color. The upper side of the abdomen is bright violet, the basis 

 of the first segment and the lateral margin steel-blue or blue-green. 

 Coxae black-green. Femora dark metallic-green. The tip of all 

 the femora and the tibiae yellow ; the four anterior tarsi become 

 dusky from the basis so gradually that it is difficult to state where 

 the infuscation begins ; on the hind tarsi the yellow coloring ex- 

 tends much farther, so that only the last joints exhibit a distinct 

 dusky tinge. The pulvilli are rather large, especially on the fore 

 tarsi, The hairs and bristles upon the feet are everywhere very 

 short, on the tibiae and tarsi yellowish, with the exception of the 

 stronger bristles at the tip of the middle tibiae. The cilia of the 

 tegulae are pale. Wings hyaline, scarcely a little tinged with 

 gray, with luteous veins, which become a little more dark towards 

 the tip of the wing ; the last segment of the fourth longitudinal 

 vein is parallel to the third and ends exactly at the tip of the 

 wing ; the posterior transverse vein lies rather exactly in the mid- 

 dle between the extreme root and the tip of the wing ; the anal 

 angle of the wings is rather protruding. 



Female. It differs from the male by the following marks : The 

 face broader, but not too much for a female ; the usual transverse 

 swelling is far below its middle. The third joint of the antennae 

 somewhat smaller than that of the male. The abdomen golden- 



