10 THE CANADIAN ENTOMOLOGIST. 



genus because, besides the differences in the venation noticed by 

 me in the description, it has no spurs on the front tibise, while such 

 spurs are distinct in Arthropeas siberica." 



In 1886 Dr. WilHston erected the genus Arthroceras (Ent. 

 Americana, II, 107), based chiefly on the character above men- 

 tioned with A. pollinosum (a new species), and A. leptis O. S. as 

 the types. That ^. /e/)/?5 belonged to the genus Arthroceras was 

 recognized by Coquillett in determining the species for Mrs. 

 Slosson's list of Mt. Washington insects (Ent. News. VI, 6, 1895). 



The two species may be separated by the following table : 



Thorax unicolor, yellowish pollinose; halteres yellow. Colorado, 

 Washington pollinosum Will. 



Thorax blackish, with two yellowish pollinose stripes; halteres 

 brown. White Mts., N. H leptis O. S. 



Both species seem to be confined to the Canadian zone. The 

 former I have received from Clear Creek, Col., May 20, 1891 

 (Oslar) ; Happy Hollow and Little Beaver, Col., July 14 and 19 

 (Gillett) . The latter has only been taken in New Hampshire, White 

 Mts., "woods and alpine" (E. P.Austin); "Alpine region of Mt. 

 Washington, at or above 5,500 ft." (Mrs. Slosson) ; "near summit," 

 Mt. Washington, July 25, 1875 (Dr. Geo. Dimmock) ; Mt. Wash- 

 ington, July 7, 1909 (F. A. Shcrriff) ; Base Station, Mt. Washing- 

 ton, July 30, 1912 (F. W. Dodge). 



The species of the genus Arthropeas are likewise comparatively 

 rare, and also seem to be confined to the Canadian zone. The 

 species may be tabulated as follows; 



Anal cell closed; wings distinctly banded; length, 



8-9 mm americana Loew. 



Anal cell narrowly open; wings not banded; length, 



12-14 mm magna, n. sp. 



Arthropeas americana Loew. 



The following brief description is given chiefly as a compara- 

 tive one to Say's Xylophagus fasciatus: 



Thorax black, covered with a yellowish pollen, leaving three 

 wide black vittse; scutellum and metanotum black; abdomen 

 yellow, basal half of the first to fourth segments black, the remain- 

 ing segments yellow; halteres entirely yellow; legs yellow, outer 

 half of the tarsi brown ; apical third of the wing smoky black, base 

 of the submarginal and first posterior, tip of the first basal, the 

 entire discal and fourth posterior and outer portion of the fifth 

 posterior cells whitish and forming a wide band across the centre 

 of the wing; the greater portion of the first and second basal cells, 

 base of the fifth posterior and tip of the anal cell and the anal 

 angle smoky black; base of the wing and greater portion of the 

 anal cell whitish. Length, 8.5 mm. 



