Diptera 65 c 
With the male are several females which I consider to be of this species. 
The description is as follows : — 
Black, less distinctly shining than the male, the thorax very densely pruin- 
escent, the centre with two narrow, pale grey vittse, and the lateral margins 
broadly pale grej'. Abdomen immaculate. Wings slightly greyish. Calyptrse 
white. Halteres yellow. 
Frons, at vertex, about two-fifths the head-width, slightly broadened 
anteriorly, each orbit at middle about one-third as wide as interfrontalia, the 
surface with many short hairs, four to six incurved bristles on lower portion 
and tw^o slightly outwardly-directed ones on upper portion; cheeks higher 
than in male and with very few short hairs above the marginal bristles. Thorax 
much less hairy than in the male, the prealar bristle absent. Abdomen pointed 
at apex. Bristling of the tibiae very variable, fore pair with zero to three pos- 
terior and zero to three postero-ventral bristles, and very rarely one antero- 
dorsal; mid pair usually with one or more ventral, two to four antero-dorsal, 
three to four postero-dorsal, and three to four postero-ventral bristles; hind 
pair with from two to five bristles on antero-ventral, antero-dorsal and postero- 
dorsal surfaces. 
Localities: one specimen with same data as male; one specimen same 
locality as foregoing but with date of July 10, 1916; one specimen. Young point. 
Northwest Territories, July 18, 1916; one specimen, cape Bathurst, Northwest 
Territories, July 26, 1916; one specimen, west of Konganevik, Camden bay, 
Alaska, July 4, 1914 (all F. Johansen). 
This species differs from any member of this genus known to me in the 
structure and armature of the hind tibiee, the bare eyes, almost bare arista, and 
black halteres. 
Limnophora Robineau-Desvoidy. 
There are two specimens in the collection referable to this genus, a male 
and a female, neither of which it is possible to identify conclusively because 
of the poor condition. The only species of the genus which I have previously 
seen from the arctics of this continent is nobilis Stein. Neither of the specimens 
before me belongs to that species, and apparently they differ specifically from 
each other also. 
The immature stages of the genus are unknown. The flies are commonly 
found close to water, being usually abundant on the shores of lakes and rivers> 
and some of the most aberrant forms occur on the seashore. 
I have found one species in Scotland feeding upon insects, but whether it 
killed, the specimens itself or merely appropriated the discarded prey of other 
predators I can not say as I did not see it catch any flies. The proposcis is 
not adapted for piercing, though armed at apex with chitinous rods which may 
serve to abrade the integument and so enable the insect to feed in a predatory 
manner. 
Limnophora, sp. 1. 
A male specimen taken at Cockburn point, Dolphin and Union strait, 
Northwest Territories, September 7, 1914 (F. Johansen), has the eyes separated 
by slightly more than the distance across posterior ocelli, the orbits narrower 
than interfrontalia at its narrowest point; arista pubescent; thorax with three 
strong pairs of postsutural dorso-centrals; presutural acrostichals irregularly 
four-rowed; abdomen with large, subtriangular, separate, brown spots; fore 
tibia with one posterior bristle; mid tibia absent; hind tibia with two antero- 
dorsal, and two weak postero-dorsal bristles; third vein bare at base; veins three 
and four divergent apically, last section of four about 2-5 as long as preceding 
section; outer cross-vein straight. 
Length, 4-5 mm. 
Vol. iii— 16963— 5 
