Osten Sacken.] 140 [October 6, 



hind tibias often with a brownish ring ; four anterior tarsi brown, the 

 root of the first joint often reddish; hind tarsi dark brown. Root of 

 the wings, as far as the humeral crossvein, slightly brownish or yel- 

 lowish; costal cell almost hyaline; stigma brown. 



Male. Similar to the female, but abdominal crossbands broader, 

 the biconvexity on their hind side stronger, and the sinus in its mid- 

 dle deeper; the gray spot on the cheeks, under the eye, often larger, 

 sometimes occupying a considerable portion of the cheek; the brown 

 ring on the hind tibiae usually expanded, so as to reach the tip of the 

 tibia?. The eyes are more distinctly pubescent, the front is beset 

 with yellow pollen, except a narrow black space above the antennae. 



Length, S ?, 10-12.5 mm. 



In drawing up the description, I had a large number of specimens 

 before me. Among them was a lot of twenty-three males and thirty- 

 five females, caught by Mr B. P. Mann, on the 7th of July, 1874, 

 almost on the same spot, in the subalpine region of Mt. Washington. 

 Another lot, of twenty-seven males and twenty females, was collected 

 by Mr. Morrison, also in the White Mountains. Other specimens 

 were from Massachusetts, Rhode Island, Canada, the Rocky Moun- 

 tains in Colorado, etc. 



This is the American representative of the European species, 

 called S. topiarius by Zetterstedt, and after him by most of European 

 writers. But it seems very doubtful to me whether these authors 

 are justified in quoting Meigen as the authority for this species. 

 Meigen's description of his topiarius does not agree with the species 

 usually understood under that name. In order to keep clear from 

 this uncertainty, I prefer to give a new name to the American spe- 

 cies. Stager (Greenland's Antliater, p. 360, 26) quotes S. topiarius 

 among the insects of Greenland. 



2. S. rectus n. sp. 



? Syrphus ribesii Linne (et auctores). 



?. Eyes glabrous; hind femora yellow, often with a brown ring 

 before the tip. 



cf. Eyes glabrous; h'nd femora black, except the tip. 



Female. Very like the female of S. torvus; the differences, as 

 given above, consist in the entirely glabrous eyes and the femora, 

 which are yellow from the very base (coxae black) ; in most speci- 

 mens the hind femora have a brown ring before the tip. 



The size, as well as the shape, of the yellow abdominal stripes are 

 very variable (the female of £. torous shows, in both respects, much 



