154 THE CANADIAN ENTOMOLOGIST 



distinguish the species from S. rectus; S. knabi and ribesii vittafrons 

 show the character very strongly, as do most of the North American 

 specimens which I have examined. 



Syrphus protritus O. S. 



Legs in both sexes wholly reddish yellow, the tarsi somewhat darker. 

 Antennae reddish. From S. rectus it is distinguished by the wholly yellow femora, 

 reddish antennae and posteriorly notched abdominal bands. There are fewer 

 black bristles on the apical half of the hind femora than in S. ribesii. 



Five specimens from Manitoba (Dr. A. J. Hunter) and one specimen, 

 Orillia, Ontario (Curran). 



Syrphus knabi Shannon. 



A large and distinct species with bright yellow bands which extend over 

 the margins in practically their full width, except in occasional males. Squamae 

 pilose above. Face wholly yellow. Legs reddish yellow, the hind femora in both 

 sexes with a brown or blackish post median band. Middle basitarsi with wholly 

 yellow bristles below, thus dififering from all other species with pilose squamae. 

 Scutellum chiefly black haired. Sides of thorax distinctly yellowish. 

 Length 11 — 12 mm. 



A common species in Ontario, where the larvae live upon aphids on elm 

 {Lanigera sp. on Ulmus). I have found two and three larvae in a single curled 

 leaf. I have also specimens from Manitoba collected by Dr. A. J. Hunter at 

 Winnipeg and Teulon. The species was originally described from Maryland 

 and Virginia. 



Syrphus ribesii L. 



Large, 11 to 12 mm. Antennae usually largely brownish, but sometimes 



mostly reddish. Abdominal venter usually with alternate yellow and blackish 

 bands, sometimes obscure or represented by isolated spots. Legs in female 

 mostly yellow, sometimes with an indistinct post median brownish band on 

 posterior femora; legs of male black on basal third of front four femora, the 

 hind femora black except the tip of apical sixth ; hind femora on apical half are 

 thickly black bristly and their tibiae bear prominent black pile on the outer side. 

 The bare eyes distinguish it at once from S. torvus ; the black spines below the 

 middle basitarsi from S. knabi; the darker antennae and more numerous spines 

 on femora as well as the more extensively black hind femora from S. vitripennis ; 

 the darker legs, antennae and larger size from S. protritus; and the fasciate 

 venter from S. rectus. 



S. ribesii is not common in Ontario, although it is met with occasionally. 

 In five years I have taken only eight specimens. It seems to be much mor'' 

 common in Manitoba, where Dr. Hunter captured some twelve specimens in 

 September. 



Syrphus ribesii vittafrons Shannon. 



Very similar to the typical ribesii but with a median brownish facial 

 stripe and the pile of the vertex more fulvous. The ventral abdominal markings 

 are very distinct so this variety can hardly be confused with other species. The 

 hind femora of the female always bear a brownish post median band. (Com- 

 mon, Ont.. Man.) 



