OBSERVATIONS ON THE MOSQUITOES OF 

 SASKATCHEWAN 



By FREDERICK KNAB 



The observations here recorded are the result of an expedition 

 to western Canada during the spring of 1907. Up to the present 

 nothing definite has been known of the habits of the mosquitoes of 

 the northern prairies. Their extreme abundance in that region 

 during the summer and the suffering they cause to man and beast 

 have been frequently reported. Their presence in such large num- 

 bers seemed the more mysterious, since water, so essential to 

 mosquito-development, is usually absent or very scarce on these 

 prairies during the summer months. However, we now know that 

 the most important part of the mosquito fauna of the northerly por- 

 tion of the eastern United States consists of species of the genus 

 Aedcs, 1 and also that these typically northern forms develop in the 

 snow-water of early spring. It was to be inferred that in the 

 prairie region of the northwest, species of Acdes of similar habits 

 would be the predominating forms, and so it proved. 



There is but one brood annually of these northern mosquitoes of 

 the genus Aedes. The adult mosquitoes live a long time (two or 

 three months) and lay their eggs late in the summer. These eggs 

 lie upon the ground until the following spring, and then hatch in 

 the water from the melted snow. With most of the species the 

 larvae develop very rapidly and often transform to adults within two 

 weeks. In order to study these mosquitoes and obtain their larvae, 

 it was necessary to be in the field with the opening of spring, for the 

 season of larval development is very brief. When the writer left 

 Washington, early in April, the magnolias were in bloom, and it 

 was thought that spring would soon open in the north. But when 

 southeastern Saskatchewan was reached, on April 10, the ground 

 was still covered with snow and the weather was cold and windy. 

 The season proved to be an exceptionally backward one, and there 

 was no appreciable change until early in May; indeed, some of the 

 large snow-drifts lasted until early in June. 



1 This name is applied as defined in Dyar and Knab : On the Classification of 

 the Mosquitoes. Canad. Entomologist, vol. xxxix, 1907, pp. 47-50. 

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