6 c Canadian Arctic Expedition, 1913-18 



Tribe LIMNOPHILINI. 



Genus Limnophila Macquart. 



Limnophila Macquart; Histoire Naturelle, Diptera; Suite a Buffon, vol. 1, p. 95; 1834. 



Subgenus Dactylolabis Osten-Sacken. 



Dactyloldbis Osten-Sacken; Proceedings of the Academy of Natural Sciences of Philadel- 

 phia, p. 240; 1859. 



Limnophila (Dactylolabis) rhicnoptiloides, n. sp. 



General colouration black, dusted with grey; wings long and narrow, the 

 veins heavily spotted and seamed with brown; Rs spurred at its origin. 



Male. — Length, 8-8.8 mm.; wing, 8-9 mm. 



Rostrum and palpi dark brownish black. Antennae black, the first segment 

 elongated. Head narrowed behind, dark coloured with a light grey pruinosity; 

 the whole dorsal surface of the head is beset with short, sharp bristles that are 

 directed forwards. 



Thorax dark with heavy, clear, light grey bloom; mesonotal praescutum 

 with four brown stripes, the median pair long and parallel. Halteres with the 

 stem pale, the knobs darker brown. Legs with the large coxae dusted with grey; 

 trochanters dark; remainder of the legs broken. Wings long and narrow, 

 subhyaline, the veins heavily seamed with greyish brown so that most of the 

 wing-surface appears of this dark colour; venation (PI. I, fig. 3) the wing of the 

 paratype is longer and narrower than that of the type figured; in both wings of 

 this paratype there is a cross-vein in cell R 2 just proximad of the radial cross- 

 vein; Rs spurred at its origin. 



Abdomen black, sparsely dusted with grey. 



Locality': Holotype, <?, Bernard harbour, Northwest Territories, July 15, 

 1915 (F. Johansen), No. 1308. Paratopotype, <?, July 22, 1915, No. 1064. 



The wings of this interesting new species are narrower, proportionately, than 

 either L. montana Osten-Sacken of eastern North America or L. damula Osten- 

 Sacken of western North America and the sector is spurred at its origin. The 

 species shows decided tendencies toward degeneration of the wings and in this 

 respect approaches L. (D.) wodzickii (Nowicky), the type of the proposed group 

 Rhicnoptila (Beschreibung neuer Dipteren, — Verhandlungen der kaiserlich- 

 koniglichen zoologisch-botanischer Gesellschaft in Wien, vol. 17, pp. 337-354, 

 PI. 1 1 ; 1867) . This last species is an even more degenerate Dactylolabis occurring 

 in the high mountainous regions (6,000 to 8,000 feet) of the Hungarian Tatras 

 (western Carpathians) where it frequents granitic cliffs in places where the rock 

 surface is constantly moistened by dripping water. Here the degenerate con- 

 dition is apparently brought about by the great altitude and the habitat. In 

 the present species the degeneracy is the result of living in the high arctics and is 

 quite comparable to the condition in L. wodzickii. In my opinion the name 

 Rhicnoptila has no status at all, although the descriptions of the immature stages 

 indicate some notable peculiarities. But whether these conditions are real or 

 due to the insufficiency of Nowicky 's description has not yet been ascertained. 



Tribe PEDICIINI. 



Genus Tricyphona Zetterstedt. 



Tricyphona Zetterstedt; Insecta Lapponica, Diptera, p. 851; 1838. 



Tricyphona brevifurcata, n. sp. 



Thoracic dorsum pale brownish grey with three conspicuous dark brown 

 stripes; wings with vein R 4 + 5 as long or longer than its fork. 

 Male. — Length, 10 mm.; wing, about 9 mm. 



