62 c Canadian Arctic Expedition, 1913-18 



about as long as apical portion of proboscis, slender. Dorsum of thorax with 

 long setulose hairs; presutural acrostichals long but not strong, irregularly 

 four-rowed; postsutural dorso-centrals four; prealar bristle very long. Abdo- 

 men narrow, sub cylindrical, sUghtly tapered posteriorly; hypopygium small; 

 fifth ventral segment almost transverse apically; -dorsum with strong setulose 

 hairs, apical and discal bristles on segments three and four. Legs stout; fore 

 tarsi similar to those of Trichopticus, short, and densely short pilose ventrally; 

 fore tibia unarmed; mid femora with slender bristles on postero-ventral s rface 

 which are longest on centre; mid tibia with two or three posterior bristles; hind 

 femora with short bristles on basal half ventrally, and an antero-ventral series 

 of long, stout bristles; hind tibia with four to five short antero-ventral, twoto 

 three longer antero-dorsal, and one long postero-dorsal, bristles. Costal spine 

 short but distinct; third vein bare, outer cross-vein nearly straight; last section 

 of fourth vein less than 1 -5 as long as preceding section. 



Length, 7-5 mm. 



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

 Territories, July, 1916 (F. Johansen). 



This species resembles in general appearance species of Trichopticus, but 

 the hind tibiae are not fringed, the tibiae of all legs are less bristly, and the mid 

 femora are normal in shape. 



Mydaeina, n. gen. 



Generic Characters: Male. — Eyes distinctly separated, narrowest part of 

 frons about one-sixth as wide as head, orbits with long hairs on entire length 

 from base of antennae to vertex; face and frons sUghtly projecting; antennae 

 short, third joint equal in length to second; arista tapered, second joint much 

 thickened, as broad as long, third much thickened at base, gradually tapering 

 to a hair at apex, the pubescence dense and short; facial ridges with moderately 

 long hairs which are carried upward half-way to base of antennae; vibrissae 

 poorly differentiated from the long bristly hairs; proboscis stout; palpi slender. 

 Dorsum of thorax with long hairs among which the dorgo-centrals are hardly 

 distinguishable; lower scale of calyptrae much larger than the upper, narrowed 

 posteriorly. Abdomen subcylindrical, with four distinct dorsal segments; 

 hypopygium small (PI. IX, fig. 31); fifth ventral segment with a broad central 

 emargination (PI. IX, 29). Legs stout, with few distinct bristles, ventral 

 surface of fore tarsal joints with dense erect pile, the bristles sparse short, con- 

 fined to margins; preapieal dorsal bristle of hind tibiae absent or represented 

 by a weak setula. Wing venation as in Mydaea, the veins without bristles. 



Female. — Differs from the male in having the frons nearly half the head- 

 width, each orbit nearly as wide an interfrontalia and with numerous long hairs, 

 an inward series directed inward, and an outer series, directed outward, longer 

 than the others; head in other respects as male, but the arista is slightly less 

 conspicuously swollen and less hairy. Thorax with the dorso-centrals more 

 distinct than in male. 



Mydaeina obscura, n. sp. 



Male and Female. — Black, opaque, the surface obscured by brownish 

 pruinescence. Calyptrae in male subfuscous, in female yellowish. Halteres 

 yellow. Wings slightly greyish, subfuscous at base. 



Head of male as in PL IX, fig. 28. Four poorly distinguished postsutural 

 dorso-centrals present; disc of scutellum hairy, margin with four bristles; sterno- 

 pleura with one large posterior bristle and many long hairs. Legs with very few 

 bristles, those on femora long but hair-like, the tibiae without well-developed 

 apical bristles, one nfear apex of dorsal surface of hind pair about as long as 

 diameter of tibia; the bristles on tibiae that ^re sometimes distinct are as follows 



