20 c Canadian Arctic Expedition, 1913-18 



seta directed proximad; on the penultimate and antepenultimate segments 

 of the abdomen the bristles are very long and delicate. The sternites (PL 

 V, fig. 59) similar, but the median bristles lie further cephalad and there is 

 a smaller tiny bristle in its individual puncture just proximad of it ; these median 

 bristles are almost in alignment with the lateral bristles. The caudal bristles, 

 three in number, are in alignment and rather widely separated. 



Colouration above dark brown, the thoracic region more reddish; a broad, 

 conspicuous dorso-median stripe reddish brown; lower surface greyish with 

 a reddish caste. Skin very smooth without tubercles or roughenings of any 

 sort. The sutures between the individual segments are very well-marked but 

 not conspicuously constricted, at about two-thirds the length of each abdominal 

 segment with a pseudosuture dividing the segment into two rings or annuli. 



Spiracular disk (PI. IV, fig. 46) surrounded by six very long, finger-like 

 lobes, of which the ventral pair are slightly the longer. All the lobes are margined 

 with dark brown and here develop long fringes of delicate pale hairs which are 

 longest at the tips of the lobes, much shortened toward the base of the lobes; 

 down the middle of the inner face of each lobe there is a long, narrow, black stripe 

 extending from the tip back toward the centre of the disk, this mark longest on 

 the ventral lobes; the lateral marks on the lobes are all expanded at their inner 

 ends nearest the spiracles, the outer margins of the ventral lobes united with one 

 another across the disk, between the spiracles, by a narrow, arcuated line. 

 Spiracles large. Anal gills short but slender, inconspicuous, the inner pair very 

 short. 



From its great resemblance to the larva of Stygeropis fuscipennis Loew of 

 northeastern America I would refer this larva to Stygeropis without question. 

 Which species it represents is somewhat doubtful, but very probably either 

 parrii or parrioides. The Tipula No. 1 of Malloch's preliminary classification 1 

 is Stygeropis fuscipennis. 



Tipuline No. 1 (Stygeropis, supposition). 



Locality: Two larvae from a lake near Bernard harbour, Northwest Terri- 

 tories, June 25, 1915 (F. Johansen). 



Two additional specimens from Demarcation point, Alaska (melted ponds 

 in tundra, May, 1914. No. 7). 



Length, 20-5-23 mm.; diameter, 1-8-2 mm. 



Form cylindrical, moderately elongated, the anterior end abruptly tapering, 

 the posterior end gradually tapering to the cauda; caudal lobes capable of close 

 application to one another along their inner faces, protecting the spiracles. 



Chaetotaxy: Dorsal segments (PI. V, fig. 60) with the setae all on the posterior 

 ring, an anterior lateral pair located in the lateral yellow line, consisting of two 

 punctures, the more lateral one of which has a tripartite bristle, the proximal 

 one simple. Nearer the caudal margin of the segments three long lateral bristles 

 in alignment and rather widely separated, the distal one located near the inner 

 margin of the yellow stripe, the inner two closer together located in the black 

 lateral stripes, the innermost on its margin. In alignment with these three and 

 located nearer the mid-dorsal region of the segment, one on either side of the apex 

 of the shield-shaped dorsal mark, are two long bristles. All of these caudal 

 bristles are in alignment with the caudal setae of the ventral segments. 



Lateral setae: On the dark pleural stripe a group of three small, stout 

 bristles on the posterior ring, arranged in a triangle; a single, longer hair on the 

 anterior ring of the segment, much closer to the ventral edge than to the dorsal 

 edge of the stripe. 



Sternal segments with the setae on the apical ring of the segment arranged 

 as in PI. V, fig. 61; there are two anterior setae on each side, and closer to the 



1 Malloch, J. R. "A preliminary classification of Diptera based upon larval and pupal 

 characters," Bull. Illinois State Laboratory of Natural History, vol. 12, pp. 199, 200, figs.; 1917. 



