72 AMERICAN DIPTERA. 



Wings with a brownish tinge; spines of the costa very short. 

 Legs entirely yellow. 



One female specimen, U. S. N. M., labelled "White Mts., Mor- 

 rison." 



Tephrochlainys riifiTeiitris Meigen. 



Length 5.5 mm. ; of wing 6.2 mm. 



Gray; abdomen reddish-yellow; cheeks whitish. 



Occiput ash-gray, front saffron -yellow to brownish, pubescent; orbits of the 

 eyes somewhat silvery-gray ; antenna; reddish-brown, the third joint nearly 

 black, arista of medium length, bare; eyes rather large, round; cheeks about 

 three-fourths the width of the eye, somewhat cream color; vibrissa; rather deli- 

 cate, one on each side; at the middle of the hind edge of the bare part of the 

 cheek is a smallish bristle. 



Thorax entirely ash-gray; dorsum pubescent, except the lateral edges; the 

 small hairs arise from small black dots, while tlie three pairs of dorso-central 

 bristles arise from large black spots; scutellum gray, yellowish at the apex, bare 

 except the ordinary four bristles. 



Propleura bare, except the one strong bristle above the fore coxa ; mesopleura 

 bare, except one small hair on the lower anterior corner; on the upper edge of 

 the sternopleura is one strong bristle and a row of smaller hairs. 



Abdomen reddish-yellow; the hypopygium of the male small; terminal seg- 

 ments in the female tapering, slender. 



Wings hyaline except the stigma, which is brownish-yellow; veins dark 

 brown, spines of the costa rather short. 



Legs yellow, all the tarsi somewhat blackish, the outer side of the front femur 

 somewhat infuscated ; middle femur slender ; hind femur rather stout; pulvilli 

 inconspicuous. 



Six males and thirty two feiiiales. Johnson, St. John's County, 

 Quebec, June 5th ; Boston, Mass., July 7th. U. S. N. M., Fran- 

 conia, N. H. Daecke, Orange Mountains, N. J., July. Melander, 

 Berkeley, Cal., March 26th ; St. Johns, Quebec, September 23rd ; 

 Pullman, Wash., March 9th. Aldrich, Friday Harbor, Wash., 

 May 28th ; Moscow, Idaho, all seasons. 



This species is very common at Moscow, Idaho, and can be found 

 on windows at almost any time during the year. 



Becker, Katalog, iv, 51, adopts Meigen's name canescens, pub- 

 lished in his Systematische Beschreibung, vi, 57, in preference to this, 

 which was published on the following page. As there is no ques- 

 tion that the two names refer to the same species, the only point at 

 issue between the two is Avhether the strict observance of page prece- 

 dence justifies the changing of a name that is in general use. In 

 this case we are in entire accord with the rules of the International 

 Congress in deciding against change. 



