172 THE BLOWFLIES OF NortH AMERICA 
hind femur with anterodorsal and anteroventral rows and a par- 
tial ventral row on apical half; hind tibia with anterodorsal row 
extending from base to apical third, two anteroventral bristles 
near middle and a series of posterodorsal bristles, the basal ones 
set close together. 
Wing (pl. 9, F) hyaline, shightly infuscated basally and an- 
teriorly; costal sections 2 to 6 in the proportion 75:52 :105:41:0; 
subcostal sclerite orange brown to black, with dark brown pile 
basally, and with long black hairs; third vein setulose from 0.25 
to 0.35 the distance to the anterior cross vein; upper and lower 
squamal lobes with dark brown pile, brown. 
Abdomen bluish black, rarely greenish and sometimes slight- 
ly purplish in certain lights, shining; all tergites with erect black 
hair; fifth sternite (pl. 20, D) as illustrated. 
Genital segments similar to those of Phormia regina. Internal 
anatomical features (pl. 20, A, B, and C) as illustrated. 
Female. Head width 11.7; length at antenna 6.7, and at 
vibrissa 7.5; eye height 5.8; head height 9.0; bueca 0.30 eye 
height; front at narrowest 0.46 head width, 0.46 at vertex and 
0.52 at lunule; outer vertical bristles long and thin; fronto- 
orbital bristles two, long, thin, proclinate or almost divaricate; 
ocellar bristles slightly divaricate. Otherwise similar to male 
except for normal sexual differences. 
Length. 6.5-8.5 mm. 
Distribution. Holaretic: North of the Arctie Cirele. From 
published reports and from specimens which have been seen 
during this study, Boreéllus atriceps (Zetterstedt) is evidently 
widely distributed in the northern part of the Holarctic Re- 
gion. It is not commonly collected. 
The above description was prepared from the following speci- 
mens: Three cotype specimens of Boreéllus aristatus, one male 
and two females (in poor condition) from Bernard Harbour, 
Northwest Territories, Canada (Canadian Arctic Expedition), 
May 1915 and 1916, and one male, Sigmia, Baffin Land, Aug. 2, 
1897 (Schuchert and White), in the U. S. National Museum; 
one paratype male of Phornmua caerulea from the type locality, 
one female, Umanak, Greenland, June 1, 1914 (M. C. Tanquary), 
one female, Nettiling Lake, Baffin Land, June 25, 1925 (J. D. 
Soper), and one male and one female, Greenland, in the Ameri- 
ean Museum of Natural History. 
The first North American record of atriceps is that by Malloch 
(1919), who redescribed it under the preoccupied name Phormia 
caerulea from specimens collected at Bernard Harbour, North- 
west Territories. Aldrich and Shannon (1923) proposed aristatus 
