194 MOSQUITOES. 



these frail flies can inflict; at times they drive everyone from 

 the boat, and trains can sometimes only run with comfort 

 on the Northern Pacific by keeping a smudge in the baggage 

 car and the doors of all the coaches open to the fumes." 



Prof. Riley Avrote the above lines many years ago, and 

 conditions have greatly changed since. The mosquito is 

 still a great pest in some places in Minnesota, sometimes 

 even killing animals that can not escape it, but the 

 prairies are rapidly settled in spite of them, and as the land 

 is gradualh" better drained mosquitoes become fewer and 

 fewer. They are very abundant north. In Davis's straits, 

 in lat. 72° N., Dr. Bessels, on board the Polaris, was obliged 

 to interrupt his observations on account of the multitudes 

 of these insects. A great number were also seen up to the 

 81st. deg. of latitude. An old ^vriter, writing about the 

 northern shores of Lake Superior, expresses himself in this 

 way: "When the mosquitoes disappeared the black-flies 

 came; the mosquito pumps up a drop of blood and flies 

 away, the black-fly bites and makes a wound which con- 

 tinues to bleed." 



In tropical America these insects are still worse, and 

 they are the source of such incessant torments that some of 

 the most beautiful regions of the globe are unfit for a white 

 population. In the llanos and prairies of Venezuela they 

 persecute cattle to such an extent that the3' do not thrive 

 even on the richest pastures. 



Of the many species found in our state a few have been 

 studied more in detail, as well as their life-history. The illus- 

 trations (figs. 154, 155, 156 and 157) show a common 

 species ( Culexpungens Wied.); it is the first seen in the spring 

 and the last to disappear late in autumn. Fig. 154 shows 

 the male, and some of the peculiar scales found upon the 

 veins of the w^ings; the first three joints of one of the feelers 

 is greatly enlarged, to show the auditor^' organ (Johnson's 

 organ). Fig. 155 shows the female, fig. 156 the full-grown 

 larva, a bunch of hairs from the tail, an egg^ mass and the 

 enlarged Q:gg\ fig. 157 shows the pupa. The color of both 

 male and female is dark gray wath lighter yellowish-white 

 bands. 



