Insect Life on Western Arctic Coast of America 31 K 



willow twigs or large plant seeds, and thus evade the notice of water birds. 

 The pupa now develops in and partly fills the case, which shows three divi> 

 first, large, swollen, cylindrical front-end with a lid, by the aid of which the ily 

 later emerged; second, a constricted "neck," and finally the "caudal" i 

 also cylindrical but smaller than the "cephalic" part, and containing jiir by 

 which the puparium rises to the surface and floats with the air chan,! 

 most. Just before the emerging of the imago the puparium becomes I'-slnpcd. 

 the neck curving so that the part of the puparium containing the pup.-. 

 touches the water-surface, and the imago can emerge by the opening of the 

 " lid." This process was observed with one of these pupa? collected July 19, 



1915, and the imago emerged four days later; from a pupa collected July \\. 



1916, the imago emerged the following day (Rearing 78). The fly itself is al>o 

 aquatic. As soon as the imago has emerged the puparium stretches out again 

 but remains floating. 



On the margin of a large lake inland from Bernard harbour, a great number 

 of freshly emerged midges of both sexes were in copula on the 15th. In the 

 marginal water were many Chironomus (pupae and adults), besides perlid and 

 trichopterous Iarva3. Branchinecta paludosa, amphipods (Gammarus limnaeus), 

 and other freshwater invertebrates were found in many of the nearby lak 



July 21-31, 1915 



Insect life is now very similar to that in the middle of July. Mosquitoes 

 (Aedes sp.) are very numerous and annoying on warm, clear days, most of the 

 larvae and pupae in the ponds having transformed (PL I, fig. 2). Various flies 

 and crane-flies (Limnophila sp., Stygeropis sp., Nephrotoma sp., Tipula sp., 

 etc.), sawflies, and parasitic wasps are common, but neuropteroid imagines 

 are comparatively few. Bumble bees (Bombus neoboreus, B. sylvicola, etc.), 

 especially the queens and workers, are busily visiting the many flowers now 

 out. Two of the willow species (Salix anglorum, S. pulchra) have now 

 dropped most of their male catkins, but those of S. reticulata are in full bloom. 

 Many butterflies (Erebia sp., Brenthis sp., Colias sp., Oeneis sp., etc.) and moths 

 are seen on clear, calm days; of the former a female specimen of Pieris occidcut- 

 alis was secured. The advent of this butterfly appears to synchronize with 

 the first blooming of the cruciferae (Sisymbrium sp., etc.) on which, probably, 

 the larvaB feed and which the imago seems to prefer. Muscid maggots were 

 noticed in rotten seal-meat, but could not be reared. 



August 1-10, 1915 



The following flying insects were noticed: 

 Bumblebees (Bombus sp.) 

 Sawflies 



Wasps. pnrasitfa (Exolytux sp., Dioctes sp.) 



Butterflies (Colias sp., Oeneis sp., Brenthis sp., Lycaena aquilo) 

 Moths (Homoglaea, Titanio sp.,, Microlepidotera, etc.) 

 Crane-flies (Erioptera sp., Tipula sp., etc.) 

 Flies 



Mosquitoes (Aedes sp.) 

 Neuropteroid imagines 



The Colias and Brenthis prefer low, grassy land or gravel supporting flowcr>: 

 the moths are found on clayey or gravelly bluffs or slopes. The mosquitoes are 

 less troublesome than in July. 



Sawfly larvse may be seen boring in the female catkins or making galls 

 upon the leaves of willows. A larger sawfly larva fed on the leaves of bushy 

 willow (Salix pulchra) from which, owing to its colour and quiescence, it is 

 with difficulty distinguished. Efforts to rear it progressed no farther than the 

 pupating stage, October, 1915. The common hemiptera (Chiloxanthes stel- 

 latus) and smaller bugs (Lobopidea sp., etc.) and the common collembola, 

 mites, spiders, beetles, caterpillars, etc., are met with. 



