40 c Canadian Arctic Expedition, 1913-18 



This may be the species recorded as pubitarsis Zetterstedt, from Greenland, 

 by Lundbeck, but so many of the northern species of Orthocladius and Chirono- 

 mus have the same habitus and general characters of colour and hairing of the 

 fore tarsi that it is not possible to say definitely whether Zetterstedt's species 

 occurs there or not without a careful comparison of a series of specimens of species 

 from Europe and Greenland. 



Orthocladius, sp. 2. 



A species represented by a number of specimens to which I have given 

 this name may not belong to Orthocladius in the restricted sense, but is related 

 to that genus. 



The colour of the larva in life is greenish or yellowish. In general form 

 the body resembles that of Campocladius, tapering to the apex and being without 

 dorsal papillae and permanently protruded blood-gills. The head is small, 

 tapered anteriorly, about as long as its greatest width, with very minute, un- 

 protruded antennae, and well developed, distinctly toothed mandibles. The 

 labial plate is armed with about eight rounded teeth, the anterior four being 

 in an almost transverse line. Thoracic pseudopods very small, armed with a 

 few black hairs at apices. Anal pseudopods at extreme apex of last segment, 

 even smaller than the thoracic pair, armed with a few black hairs and some 

 curved thorns at apex. Body without surface hairs. 



Length, 3-5-4-5 mm. 



Locality: Demarcation point, Alaska, May 16, 1914, in mud of freshwater 

 ponds (F. Johansen). 



Genus incertus. 



A larva and pupa from the stomach of the Great Lake-trout (Cristivomer 

 namaycush) belong to a genus unknown to me. It is my opinion that the genus 

 belongs to Tanypinae, but so little is known of the immature stages of the aberrant 

 genera of Chironominse that I cannot be absolutely certain of the relationship 

 of the rather imperfect specimens before me. 



Larva. Testaceous; posterior margin of head, apices of mandibles, and 

 lateral portions of labium dark brown. 



Head with sparse, long, erect pale hairs; antennae either retracted or missing; 

 mandibles very long, apex terminating in a long, slender, sharp tooth, inner 

 margin with three widely spaced, short, truncated teeth; maxillary palpus 

 short, not over 1-5 as long as thick; labium without distinct teeth, minutely 

 irregularly serrated anteriorly, its anterior outline produced anteriorly in centre; 

 hypopharynx with eight to ten small teeth on each side above lateral dark 

 areas of labium; ventral surface of head with a narrow pale central stripe, bor- 

 dered on each side with blackish brown. Anterior pseudopods short and stout, 

 armed apically with many stiff hairs; body without noticeable hairs; anal 

 pseudopods stout, with apical retractile claws; dorsal papillse about three times 

 as long as thick, each with about six apical hairs; two apical respiratory pro- 

 tuberances at base of pseudopods dorsally, their length about three times their 

 width, apices sharp. 



Length, 15 mm. 



Pupa. Testaceous. Head missing. Prothoracic respiratory organs not 

 elevated (possibly missing); wings extending to middle of second abdominal 

 segment; none of the tarsi exceeding apices of wings, the fore and hind legs with 

 the tibiae and tarsi straight, the mid pair with the tibiae and tarsi forming a 

 double curve. Incisions between abdominal segments marked by a dark brown 

 line on dorsum and venter; each segment except first and last with three long, 

 slightly flattened hairs on each side; penultimate segment with two large down- 

 wardly projecting, posteriorly flattened, projections on posterior margin, which 

 are separated by a distance about equal to their own width; apical segment 



