18 c Canadian Arctic Expedition, 1913-18 



Locality: One large larva taken in the melted ponds in the tundra at 

 Demarcation point, Alaska, May, 1914 (F. Johansen). 



Length, 19-5 mm.; diameter, 2-4 mm. 



Form cylindrical, the anterior segments narrower, the abdominal segments 

 just before the cauda swollen. Body with a covering of short and delicate 

 appressed hairs. Head-capsule of the long narrow structure of the tribe; 

 mandibles (PI. V, fig. 55) long, sickle-shaped; maxilla (PI. V, fig. 54) with the 

 outer lobe projecting from the oral opening when the head is completely retracted. 

 Colouration uniform light yellow throughout. Spiracular disk (PL IV, fig. 

 44) small, with four lobes, the lateral and ventral pairs. Lateral lobes rather 

 short and blunt, the ventral edge with an irregular linear brown mark, the outer 

 edge with a dense fringe of long hairs; ventral lobes longer with a long, arcuate, 

 brown line down the inner face; outer edge with a dense fringe of long hairs, 

 those at the tip being very elongate. Anal gills four, short, blunt, oval. 



TIPULINI. 



A considerable number of Tipuline forms were included in the present 

 collection. Only one of these, Tipula arctica Curtis, was reared and the generic 

 reference of the remainder must be considered as being somewhat doubtful. 

 I have studied each of these species, however, in the light of our knowledge of 

 other life-histories, and have placed them as closely as the data will warrant. 



Tipula arctica Curtis. 



Locality: Larvae in the ground at Bernard harbour, Northwest Territories, 

 May 27, 1916 (F. Johansen). 



A male collected as a larva on May 27 pupated about June 20. (Rearing 

 No. 106.) 



Larvae. Length, 23-25 mm.; diameter, about 4 mm. 



Form cylindrical. Mouth-parts with the mentum (see PI. V, fig. 53) 

 long and slender with a large, blunt, median tooth and two smaller teeth on 

 either side; directly beneath these lateral teeth similar subequal teeth are 

 (hypopharynx) visible. Labrum as in PI. V, fig. 52. 



Chsetotaxy: Dorsal surface, a transverse row of delicate hair-like setse 

 across the dorsum of the last thoracic segment and the abdominal segments, 

 there being usually four of these punctures on the first three segments occurring 

 at about mid-length of the segments; on the abdomen they lie on the posterior 

 ring of each segment (see PI. V, fig. 56) ; the lateral puncture bears two bristles, 

 the inner punctures a single seta; they correspond exactly to the condition of 

 the ventral segments except that here the solitary anterior bristle has moved 

 caudad into alignment with the posterior paired bristles. In some there are 

 a few weak supplementary bristles in the same line. Ventral surface (PI. V, 

 fig. 57) similar; two prominent widely separated setigerous punctures, each with 

 two long bristle-like hairs nearer the caudal margin and two other smaller and 

 more delicate bristles slightly cephalad and closer to the median line; these 

 anterior ventral bristles are separated from one another by a distance that is 

 a little less than the distance between them and the larger posterior bristles; 

 on the lateral margin of the segment there is usually a more delicate hair. 



Colouration dull yellow, the thoracic segments with abundant, tiny, appressed 

 dark hairs that give a darker appearance to the anterior end of the body. 



Spiracular disk (PI. IV, fig. 45) surrounded by six short lobes, a dorsal 

 pair, rather closely approximated medially, a dorso-lateral pair and a ventral 

 pair. The dorsal pair are shorter than the lateral pair and the inner face in 

 most specimens has a straight or slightly curved, dark brown, line. The lateral 

 lobes are longer and more slender. The ventral lobes are short and broad. 



