10 c Canadian Arctic Expedition, 1913-18 



brown; a very narrow and indistinct median brown- line. Male hypopygium 

 with the ninth tergite (PI. II, fig. 27) short, rather tumid, the caudal margin 

 with a broad, U-shaped, meciian 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 bristles. 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 slightly dorsad, the blunt apex bent very slightly 

 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, &, west of Konganevik, Camden bay, Alaska, June 

 1914 (F. Johansen). No. 634. Paratopotypes, seven c?'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-x 

 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 min. 



Palpi black. Frontal prolongation of the head short, black; nasus elongate, 

 black. Antennae black, the basal enlargement of the flagellar segments not 

 conspicuous (PI. 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 foveas 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 M^; 

 indistinct seams along Cm and its branches; veins black; venation (PI. I, fig. 6) 

 Rs rather long for this group of flies, a httle longer than ^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-dorsal line. Male hypopygium with the ninth tergite 

 (PI. Ill, fig. 28) quadrate, the caudal margin with a small, deep, U-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 (PI. Ill, 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 



