Diptera 43 c 



in colour evident from the above description there are no long erect dark hairs 

 on thoracic dorsum as in that species. 



Length, 2-3 mm. 



Type locality: Hood river, Arctic sound, Northwest Territories, August 28, 

 1915 (R. M. Anderson). Paratypes, Bathurst inlet, Northwest Territories, 

 September 1, 1915 (R. M. Anderson). 



This species is closely related to ardicum Malloch, described from British 

 Columbia, but the points mentioned in the description should serve to separate 

 the species. 



Simulium, sp. 2. 



Pupa. — This species is similar to johannseni Hart in having the thoracic 

 respiratory organs each four-branched (PL VI, fig. 4); There is also a Euro- 

 pean species with this characteristic. From johannseni the present species 

 differs in the armature of the abdomen. The third and fourth dorsal segments 

 each have eight stout anteriorly directed thorns near the posterior margin, in a 

 transverse series, four on each side, the space between each series of four about 

 three times as wide as the space between the thorns of each series; dorsal seg- 

 rnents five to eight inclusive, each with a transverse series of weak, backwardly 

 directed spines near anterior margin, the series of fifth segment much shorter 

 than that on sixth, those on other segments becoming progressively longer and 

 stronger as they near apex; apical segment with two short spines; fourth, fifth, 

 and sixth ventral segments each with two short spines on each side. 



Length, 3 mm. 



Locahty: Bernard harbour, Dolphin and Union strait. Northwest Terri- 

 tories, August 16, 1915, in bed of river (F. Johansen). 



Simulium, sp. 3. 



Pupa. — Differs from the foregoing in having the thoracic respiratory organs 

 each with twelve or thirteen branches (PI. VI, fig. 13) and the armature of the 

 abdomen as follows. Third and fourth dorsal segments each with eight very 

 small recurved thorns arranged as in the previous species, fifth segment with 

 the anterior transverse armature almost imperceptible, that on sixth, seventh, 

 and eighth consisting of a series of very small, closely placed spinules that 

 extends entirely across the surface from side to side; apical segment with two 

 very conspicuous upwardly curved thorn-like processes, fifth ventral segment 

 with a pair of small thorns on each side near posterior margin, sixth and seventh 

 each with one such thorn similarly located. 



Length, 3 • 5 mm. 



Locality: Bernard harbour. Dolphin and Union strait. Northwest Terri- 

 tories, July 10, 1916 (F. Johansen). 



Simulium, sp. 4. 



Pupa. — Differs from the . previous species in having sixteen-branched 

 thoracic respiratory organs (PL VI, fig. 12). The abdominal armature is as 

 follows: second dorsal segment with eight minute spines on each side — three in 

 a submedian transverse group, three in a sublateral similarly disposed group, 

 and two midway between these groups; third and fourth segments each with 

 the same number of spines as second, but they are stronger, more appreciably 

 recurved apically, and the submedian and intermediate series are not so distinctly 

 separated and appear as a single rather irregular series of five thorns; fifth and 

 sixth segments without well-developed spinules anteriorly; seventh and eighth 

 each with a complete series of spinules near anterior margin; apical segment 

 wiih two to three small spines on each side; third ventral segment with tAvo 

 thorns on each side, fourth with three, fifth with two, and sixth with one. 



