ENTOMOLOGICAL SOCIETY OF ONTARIO. 57 



Mosquitoes. 



No insect causes so much annoyance and actual suffering to the human race as the 

 Mosquito. It is everywhere prevalent in the summer time and in many localities is so 

 excessively abundant as to be an intolerable pest. Though only active in warm weather 

 it seems that no amount of cold will destroy it. It occurs in prodigious numbers in our 

 Northwest Territories, and, if the travellers' tales from the Yukon and Klondike may be 

 credited, it swarms within the Arctic Circle in such myriads that human beings can hardly 

 live under its overwhelming and incessant attacks. 



Though so common an insect and so obtrusive in its onslaughts upon entomolo- 

 gists as well as upon ordinary mortals, it is a remarkable fact that almost nothing was 

 known about the American species till they were recently studied by Dr. L. O. Howard, 

 of Washington, and the results of his observations were published in the volume men- 

 tioned at the beginning of this paper. Writers have been content to quote the descrip- 

 tions given by Re'aumur of a European species, which he studied at Paris one hundred 

 and fifty years ago, and have taken for granted that his careful and accurate records made 

 in France are applicable, without verification, to the numerous species that inhabit North 

 America. That the species are numerous, notwithstanding the general practice of speak- 

 ing of "the Mosquito " as if there were but one kind from the Atlantic to the Pacific, is 

 shown by the fact that Mr. Ooquillett has determined twenty distinct species in the col- 

 lection of the National Museum at Washington, and there is good reason to believe that 

 not half the existing species are represented there. 



Fig. 35. — Female mosquito (Oulex puwjens), side view— much enlarged. (After Howard.) 



Dr. Howard has made Culex pungens (Fig. 35) a species common at Washington, the 

 subject of his special studies, and we may present here a condensed account of his history 

 of its life as being typical of any species with which we may be troubled. The eggs are 

 laid on the surface of water in masses containing from 200 to 400. As seen from above, 

 the egg-mass is gray brown; from below silvery white, the latter appearance being due 

 to the air film. The eggs laid during the night began to hatch at two o'clock in the 

 afternoon of the same day during warm weather towards the end of May, but in cooler 

 weather they sometimes remained unhatched until the second day. 



The larvse (Fig. 36) issue from the under side of the egg masses and are extremely 

 active at birch. In general they pass through apparently three different stages, reach 

 maturity and transform to pupse in a minimum of seven days When nearly full-grown 

 their movements were more carefully studied as they were more easilv observed than 

 when newly hatched. At this time the larva remains near the surface of the water, head 

 downwards, with its respiratory siphon, which takes its origin from the eighth abdominal 

 segment at the exact surface and its mouth filaments in constant vibration, directing food 

 into the mouth cavity. Occasionally the larva descends to the bottom but never remaias 

 below the surface for more than a minute at a time. In ascending it comes up with an 

 effort, with a series of J9rks and wriggliDgs with its tail, but descends without difficulty, 

 its specific gravity seeming to be greater than that of water. 



