The mosquitoes of Canada

As in most other aquatic Diptera, the pupal case of the moiquito ruptures middorsally along the thorax and the adult e-e.ges into the air, the surface tension of the water preventing it from getting wet. [...] The presence of Aedes cataphylla in the vicinity of Kamloops, B. C., and of spencerii on the prairies advances the mosquito season to the same time as, or even ahead oi that of southern Ontario, where the common species are rather late in emerging, although the mean temperatures in April at Kamloops, B. C., and at Windsor, Ont., are warmer than those in the Prairie Provinces. [...] The membrane lying between the probasisternum and the fore coxa, the anteprocoxal membrane, and the membrane between the fore coxa and the mesothorax, the postprocoxal membrane, may each bear scales in some species of Aedes. [...] In Aedes campestris, dorsalis, and trivittatzs, the scales of the upper half of the postpronotum and the adjacent edge of the scutum match those of the single middorsal stripe, giving a tripartite appearance to the thorax, as shown in Fig. [...] The central region of the postsutural part of the scutum between the wings is the prescutellar depression.