snow: syrphidae. 37 



Syrphus pauxillus Williston. 



Two specimens from Colorado undoubtedly come here. The species 

 was described from a single male specimen. A female specimen offers 

 the following differences or additions: Length nine millimeters, meso- 

 notum more greenish black or bronze, the pile obscure whitish; fifth 

 abdominal segment without yellow spots on the anterior angles ; legs 

 yellow, with the basal half of the front and middle femora, the hind 

 femora except the tip, a broad band on the hind tibiae, and the hind 

 tarsi, black. 



Syrphus ribesii Limie. 

 'Five specimens, Colorado. 



Syrphus aniericanus Wiedemann. 

 Numerous specimens, Colorado. 



Syrphus umbellatarum Schiner. 



Five female specimens, Colorado. The only western locality here- 

 tofore given is Arizona (Williston). 



Allograpta obliqua Say. 

 Five specimens, Colorado. 



Mesogramma marg-inatum Say. 



Numerous specimens from Colorado, showing very great variation. 



Sphaerophoria cylindrica Say. 



Twenty specimens, Colorado. I think the specimens belong here, 

 though a positive identification is hardly possible at present. 



Rhing'ia nasica Say. 



One specimen, Colorado. This is the first time that this species 

 has been recorded from beyond the Mississippi. 

 Copestylum marginatum Say. 



Two specimens, Colorado, representing the extremes of variation in 

 the species. The male corresponds to C. Iciiiiiin Williston. Speci- 

 mens of this species were bred from Opiintia viissouricnsis, in company 

 with others of Volucella fasciata Macq. 

 Sericomyia militaris AValker. 



Sixteen specimens from Minnesota and Colorado vary in the mark- 

 ings of the second abdominal segment, and in the color of the legs. 

 Some have no spots at all on the second segment; in others the two 

 yellow dots are conspicuous, approaching, in size and shape, the 

 markings of the third segment. The tibiae vary from light yellow to 

 reddish brown. 

 Brachyopa cynops, n. sp., plate vii, f. 2. 



Head light yellowish brown, largely concealed beneath light glisten- 

 ing pollen ; the shining ground color shows just above the antennae 



