226 KANSAS UNIVERSITY QUARTERLY. 



Omegasyrphus sp. 



Male. Metallic green, slender species, with short antennae, simi- 

 lar to O. balioptents Loew and coarctatus Loew. Front narrowed in 

 the middle, upper half very tumid, shining greenish black, with 

 whitish erect pile; lower half depressed, flat, covered except in the 

 middle with whitish appressed pile. Antennae brownish black, very 

 short; first joint short and rather thick, third joint hardly as long as 

 the frrst, second joint one-half the length of the third; arista basal, 

 short and slender. Face tumid, black with a slight greenish tinge, 

 silvery pilose. Eyes bare, below with some very short, sparse, hardly 

 perceptible pile. Thorax punctate, green, little shining, with a 

 median geminate copper coloreil stripe and similarly colored lateral 

 stripes. Scutellum concolorous, the tip emarginate and with two 

 short spinous projections; metathorax metallic bluish black. Abdomen 

 punctate, brassy metallic green, moderately shining; second segment 

 wider than the others, with tumid sides. Pile of the whole body 

 whitish, glistening. Fegs fulvous brown, femora blackish, except at 

 the base and at the tips; hind metatarsi thick, as long as the following 

 joints. Halteres yellow. Wings cinereous hyaline, broadly infus- 

 cated along the veins; the costal, marginal, submarginal, and the first 

 basal cells are almost altogether filled out with fuscous; the exterior 

 end of the discal and first posterior cells are rounded posteriorly and 

 from the latter there hangs the short stump of a vein. — Length 7 mm. 



One specimen. Garden ofthe Gods, Colorado Springs, Colo. (July). 



This species differs from O. balioptei'us Loew, in general color and 

 in the color of the front, which is black and not resplendant coppery; 

 it has shorter antennse, a widened second abdominal segment and no 

 black pile on the sides of the abdomen; the fuscous black of the 

 femora is not confined to the basal half. It is apparently distinct 

 from coarctatus Loew, in its constricted front, shorter third antennal 

 joint, and more infuscated wings. 



Chrysotoxum ypsilon Will. 



A single very large female from the Magdalena mountains, N. M. 

 (July), measuring 17 mm., agrees almost perfectly with the descrip- 

 tion. The four front femora are black at the base. The three types 

 were also from New Mexico. 



Chrysotoxum derivatum Walk. 



Ten specimens, Manitou Park, Colo. (July and August); four spec- 

 imens, Estes Park, Colo. (August); one specimen, Colorado (Gillette, 

 No. 544). A western and northern species. The characters used 

 for separating the species in this genus are very unsatisfactory. They 



