Diptera 39 c 



labium with nine distinct teeth, all of which are rounded at apices, the central 

 one much broader than the first lateral and slightly shorter; surface of the head 

 with the usual hairs. Dorsum of each thoracic segment with four to six long 

 hairs; thoracic pseudopods stout, armed at apices with weak, pale hairs. Dorsal 

 apical papilla very slightly elevated, each armed with six dark brown hairs; 

 four short, stout, respiratory protuberances caudad of d'orsal papillse and between 

 anal pseudopods, the latter stout and short, the apical armature consisting of 

 rather stout pale thorns. 



Length, 8-9 mm. 



Locality: Brackish pond at Bernard harbour. Dolphin and Union strait, 

 Northwest Territories, June 6, 1916 (F. Johansen). 



Along with this species is one of Orthocladius sp. 2. There are no well- 

 defined larval cases in the vial with the larvae, and only one rude cylindrical 

 " runway " similar to those of Chironomus species. 



Tanytarsus, sp. 4. 



This species is much smaller than the preceding, being about 5-6 mm. in 

 length, and forms a cylindrical case which is very little longer than the larva and 

 is entirely covered with fine particles of sand. There are no filament-like pro- 

 tuberances on the cases before me such as are on cases of some members of this 

 genus found in streams in the more temperate portions of this continent. 



Structurally the larva resembles the preceding species, but the labium is not 

 so straight on its anterior outline laterally, being more like that of Orthocladius 

 nivoriundus Fitch, the central portion being almost transverse, with broad, 

 poorly defined teeth, and the lateral portions sloping backward, with sharp teeth. 

 The antennae are almost as in the preceding species. 



, LocaUty : Bernard harbour, Dolphin and Union strait, Northwest Territories, 

 from bottom of big lake (20 feet), middle of February, 1916 (F. Johansen). 

 Another vial with date December, .1915, station 42y, contains a large number of 

 these larvae. 



Catnptocladius Van der Wulp. 



Four specimens in the collection appear to belong to this genus. They are 

 all males, but their condition is too poor to enable me to make certain of even 

 their generic status. They, however, have the habitus of Camptocladius and 

 probably belong here. 



Length, 2-5 mm. 



Locality: Bernard harbour, Dolphin and Union strait. Northwest Territories, 

 June 18, 1915 (F. Johansen). 



Orthocladius Van der Wulp. 



This genus is well represented in northern latitudes; the species occur in the 

 United States very early in the year, March and April being the months in which 

 they are most abundant. 



There is one imago of a species in this collection and the larvae of one, which 

 may or may not be the same species. 



Orthocladius, sp. 1. 



A male in poor condition closely resembles nivoriundus Fitch, but the fore 

 tarsi have much longer hairs, the basal fore tarsal joint is slightly less than three- 

 fifths as long as fore tibia, the wings are milky, and the cross-vein is obUque. 



Length, 6 mm. 



Locality: Colhnson point, Alaska, June 22-23, 1914 (F. Johansen). 



