10 c Canadian Arctic Expedition, 1913-18 
brown; a very narrow and indistinct median brown line. Male hypopygiiim 
with the ninth tergite (PL II, fig. 27) short, rather tumid, the caudal margin 
with a broad, U-shaped, median notch, the caudal margin densely provided 
with short, black hairs; beneath the tergal lobes, between the pleurites, are 
two small rounded lobes that are densely set with short black l;)ristles. Ninth 
pleurite extensive, oval, with numerous hairs; outer pleural lobe (PI. II, fig. 22) 
almost circular in outline, the outer face with numerous short hairs; inner 
pleural lobe (PI. II, fig. 25) of rather simple structure, two armed, the outer arm 
directed caudad, at its tip forming a blackened chitinized hook; the inner arm 
is directed proximad and shghtly dorsad, the blunt apex bent very shghtly 
cephalad, almost the whole appendage with dense, pale hairs that are short 
or absent on the apex of the lobe, longest on the inner margin; viewed from above 
it is seen that this inner arm sends out a lobule on the inner dorsal side before 
the apex; the dorsal margin of this lobule is narrowly but heavily chitinized. 
Suture between the ninth sternite and pleurite not very distinct, the sternal 
region destitute of hairs. 
Locality: Holotype, d", west of Konganevik, Camden bay, Alaska, June 
1914 (F. Johansen). No. 634. Paratopotypes, seven ct's, Nos. 635, 636, 
June 1914; Nos. 433, 437, 439, 440, and 441, July 4, 1914. 
Genus Nephrotoma Meigen. 
Nephrotoma Meigen; Illiger's Magazine, p. 262; 1803. 
Nephrotoma arcticola, n. sp. 
General colouration black; abdominal tergites with an interrupted orange- 
yellow stripe on either side of the median line; wings hyaline with the stigma 
dark brown; a brown cloud at the end of the sector. 
Male. — Length, 12-5-13 mm.; wing, 12-13-2 mm. 
Female. — Length, 14 mm.; wing, 13 mm. 
Palpi black. Frontal prolongation of the head short, black; nasus elongate, 
black. Antennae black, the basal enlargement of the flagellar segments not 
conspicuous (PL II, fig. 14). Head broad, black, faintly shiny; the vertex 
surrounding the antennal bases yellow. 
' Pronotal scutum black, scutellum yellowish. Mesonotum black, faintly 
shiny; in some specimens a narrow yellowish line on the praescutum near the 
suture and a yellowish mark before the pseudosutural fovese indicate the usual 
yellowish ground-colour of the thorax in this genus of flies. Pleura black, 
faintly dusted with grey; dorso-pleural membranes dull yellow, a linear yellow- 
ish mark on the side-pieces of the mesonotal postnotum just in front of the 
halteres. Halteres dark brown, the head somewhat yellowish. Legs with the 
coxse dusted with grey; remainder of the legs dark brown. Wings whitish 
hyaline, the costal and subcostal cells not brighter; stigma small, dark brown; 
a paler brown cloud at the end of the sector, extending down to cell first Mi', 
indistinct seams along Cu and its branches; veins black; venation (PL I, fig. 6) 
Rs rather long for this group of flies, a little longer than i?2+3; cell Mi sessile 
or very short-petiolate. 
Abdomen greyish black; lateral margins of the tergites very narrowly 
paler, in some specimens a broad, interrupted, sublateral orange-yellow stripe 
on either side of the mid-doi'sal line. Male hypopygium with the ninth tergite 
(PL III, fig. 28) quadrate, the caudal margin with a small, deep, LT-shaped, 
median notch, the lateral lobes squarely truncated, finely spiculose, the outer 
lateral angle with a blunt point that is minutely toothed beneath. Outer pleural 
appendage (PL III, fig. 29) an elongate-oval lobe that is produced into a blunt 
point at the tip; inner pleural appendage chitinized and at its tip produced 
into a short beak; pleural suture rather long, at its inner end curved slightly 
