Diptera 37 c 



CHIRONOMIN^. 



There are representatives of several genera of this subfamily in the collection, 

 some of them represented by larval and pupal stages and some by imagines. 



Diamesa Meigen. 



This genus is represented in the collection by one species which does 

 not agree in structure with any species known to me. 



The larvae of Diamesa species are generally found in fast running water 

 and normally on rock surfaces. I have seeii females that were collected while 

 in the act of ovipositing in water caused by the melting of snow on mountains 

 in Montana. 



Diamesa arctica, n. sp. 



Female. — Black, subopaque. Wings subfuscous, veins thick and dark, 

 cross-vein infuscated. Halteres brown. 



Eyes very widely separated, width of frons equal to one-half the width 

 of head; antennae with 8 joints, the apical one four times as long aspreapical, 

 surface hairs long and rather numerous. Pronotum with a deep, moderately 

 wide central, wedge-shaped incision; dorsum of mesonotum and scutellum 

 with rather long fuscous hairs. Abdomen stout, with shaggy fuscous hairs. 

 Legs stouter than in Waltlii Meigen, and with much more conspicuous hairs; 

 fore tarsi with the basal joint very little more than one-half as long as fore 

 tibia; fourth tarsal joint on all legs sub-equal to or very little shorter than fifth; 

 mid tarsi with a series of minute erect setulae on ventral surface of at least 

 the basal two joints. Venation similar to that of Waltlii. 



Length, 4-5 mm. 



Type locality: Colville mountains, Wollaston peninsula, Victoria island, 

 July 22, 1915 (D. Jenness). Paratype, lake Angmaloktok, Colville mountains, 

 Wollaston peninsula, Victoria Island, July 29, 1915 (D. Jenness). 



Chironomus. 



There are larvae and pupae of one species and one imago of possibly another 

 species of this genus in collection. 



Chironomus, sp. 1. 



A male in rather poor condition resembles closely several species I have 

 described from Pribilof islands. It is entirely black and has the fqre tarsi 

 long-haired, characters common to nearly all males of this genus I have seen 

 from the far north. Structurally the specimen agrees very well with one 

 I have described as conformis in a paper now in press, but more specimens 

 are necessary to ensure an authentic identification. 



Length, 7-5 mm. 



Locality: Bai'ter island, Arctic coast of Alaska, July 2, 1914 (D. Jenness). 



Chironomus, sp. 2. 



Lakva. Bright red in life. Labium very similar to that of tentans 



Fabricius, but the median tooth is regularly rounded and the small submedian 

 one larger than in that species; the mandible has three teeth in addition to the 

 large apical one. The ventral and respiratory filaments are absent, the dorsal , 

 papillae are small, each with eight long hairs, and the four apical respiratory 

 protuberances between the caudal pseudopods are about three times as long as 



thick. 



Length, 17-19 mm. 



