1915.] NATURAL SCIENCES OF PHILADELPHIA. 497 



narrowly split by a pale middle vitta, lateral stripes quite indistinct; 

 scutum yellowish brown with the lobes darker, grayish; scutellum 

 yellowish brown; postnotum light gray. Pleura clear light gray, 

 with the membranaceous area yellowish. Halteres rather short, 

 brown, the knobs dark brown with the apex more yellowish. Legs 

 with the coxse brown with a sparse grayish bloom; trochanters dull 

 yellow; femora brownish yellow, narrowly tipped with dark brown; 

 tibiae and tarsi brown. Wings light grayish brown, the costal region 

 scarcely darker, the wing-apex darkened; stigma dark brown; a 

 broad vitreous antestigmal band and a large vitreous spot beyond 

 the stigma in the apex of cell second Ri and base of cell R2. 



Abdominal tergites one and two yellowish, the remainiag tergites 

 dark brown with a narrow dark brown median vitta; a narrow 

 caudal margin of yellowish silver; sternites yellow with a broad 

 median triangle on segnients five to seven with the apex of the 

 triangle at the caudal margin; segments eight and nine brownish 

 yellow; hypopygium enlarged. Male hypopygium with the ninth 

 tergite large, prominent, the dorsal surface flat or a little convex; 

 the caudal margin with a very deep V-shaped notch, the lateral 

 lobes a little produced on the outer side. Ninth sterno-pleurite 

 somewhat restricted, the pleural suture not well indicated, the 

 pleurite lying on the dorso-caudal face of the sternite; outer pleural 

 appendage a very slender filiform lobe, fleshy, pale, with long hairs; 

 inner pleural appendage complex, the caudal lobe produced into a 

 slender curved hook which is bent upward; the inner lobe is fiattened? 

 the anterior margin blackened and heavily chitinized, deeply notched; 

 the blade with a protecting mantle of delicate fine ribules (as in 

 monticola) . Ninth sternite darker colored than the pleurite and 

 provided with a few scattered hairs, deeply notched medially; a 

 stout pendulous lobe which bears a dense tuft or pencil of long 

 reddish hairs, this pencil directed ventrad. Eighth sternite large, 

 prominent, extending far caudad and its concavity forming a sheath 

 for the base of the ninth sternite; the lateral angles bear dense 

 tufts of long, stout, reddish-silvery hairs which are decussate; be- 

 tween these lobes a broad median projection whose lateral angles 

 are slightly recurved and whose caudal margin is broadly concave; 

 this latter lobe is hidden by the prominent tufts of hair. 



Habitat. — Arctic America. 



Holotype, cf, Hudsons Bay Territory, Canada (Kennicott). 



The type is in the collection of the Museum of Comparative 

 Zoology, where the specimen bore in Loew's writing the name adopted 

 herein. 



