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, subcylindrical, slightly 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, two to 
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 slightly 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 dorso-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; preapical 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 PI. 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 near apex of dorsal surface of hind pair about as long as 
diameter of tibia; the bristles on tibiae that are sometimes distinct are as follows • 
