40 c Canadian Arctic Expedition, 1913-18 
This may be the species recorded as puhitarsis 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 know^i 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 papTllse 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 respiratorj^ 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 
