42 c Canadian Arctic Expedition, 1918-18 



This species resembles pleurale Malloeh in having the mesopleura hairy 

 on the supper portion. The third branch of radius in pleurale is very distinctly 

 furcate, which is not the case in borealis. ^ 



A female which is in rather poor condition appears to belong to this species. 

 In colour it is identical with the male, but it is not possible from the condition 

 of the specimen to say whether the mesopleural hairs are present or not. The 

 claws are bifid, as in pleurale, but the third branch of radius is as in the male 

 of borealis. The basal joint of the hind tarsus is of equal thickness throughout 

 its length, its apex is not produced on posterior side, and its length equals 2 ■ 5 

 the length of second. 



Locality: Bernard harbour, Northwest Territories, August 25, 1916 (F. 

 Johansen) . 



Sitnulium Latreille. 



There are imagines of two species of this genus in the collection. It is not 

 possible to definitely associate the larval and pupal material in the collection 

 with the adults as no specimens were reared. It is highly probable that the 

 pupae I describe in the following pages belong to species represented in the adult 

 -forms, but there appear to be three distinct species in the former and only two 

 in the latter. Unless the species which has sixteen-branched respiratory organs 

 is that of Prosimulium borealis, which does not appear probjible from what I 

 know of the pupse of that genus, there must be a third species that occurs at 

 Bernard harbour. 



Sitnulium, sp. 1. 



This species closely resembles venustum Say in colour, but is larger than the 

 average for that species, being nearly 3 mm. in length. The specimen is in such 

 poor condition that it is impossible to tell whether the scutum is marked or not. 

 The abdomen has the characteristic colouring of the venustum group, the basal 

 four segments being opaque black and the apical five shining black dorsally. 

 The legs are black, with the fore coxae, trochanters, bases of all femora (narrowly), 

 basal half of all tibiae, basal two-thirds of hind metatarsus, and basal half of 

 gecond joint of hind tarsus pale yellow. Mid tarsi missing. Wings clear. 

 Haltferes yellow. 



It is impossible to say anything about the structure of the tarsal claws as 

 the only pair that are left are stuck fast in the mounting medium, and are not 

 visible to the extent of showing if they are simple or not. 



Locality : Hood river, Arctic sound. Northwest Territories, August 28, 1915 

 {R. M. Anderson). 



Simulium sitnilis, n. sp. 



Female. — Similar to arcticum Malloeh in general coloration and'in structure, 

 of tarsal claws. 



Black, subopaque, covered with whitish pruinescence. Antennae, palpi, 

 and proboscis entirely black; front, and face with dense whitish pruinescence', 

 the former very faintly shining; hairs of face and frons whitish yellow, those on 

 vertex and upper part of occiput partly brown. Dorsum of thorax, when seen 

 from the front, with an indistinct, broad, whitish pruinose vitta on each side of 

 median fine, when viewed from behind with the vittae less distinctly whitish 

 than the area behind each anterior lateral angle; pile of dorsum all hair-like, 

 rather short and depressed; no erect dark hairs distinguishable. Abdomen with 

 basal four segments opaque; the apical five segments very faintly shining; 

 surface hairs all yellowish. Legs black, basal two-thirds of fore tibiae dorsally, 

 basal third of mid and hind tibiae, basal third or basal joint of mid tarsi, basal 

 two-thirds of basal and basal third of second joint of hind tarsi yellowish. The 

 tarsal claws are similar to those of arcticum Malloeh, but besides the differences 



