u 



DIPTERA OF MINNESOTA. 



^^^J 



and not too deep. Open tanks and cisterns, drains, ditches, puddles, 

 shallow ponds, post holes, depressions under side walks, watering 

 troughs where the water remains unchanged for some time, muddy 

 holes made by the feet of cattle and other stock, marshy places, old 

 ."^ basins, tin cans, bottles, broken crockery, 



cess-pools and rain barrels are a few of 

 the places chosen by these pests in which 

 to deposit their eggs ; any place, in fact, 

 that will hold half a pint of water for ten 

 or twelve days may be the source of a hun-' 

 dred or more. Even if the water almost 

 dries up in depressions where the eggs 

 have been laid, or where the young "wig- 

 glers" are living, if it is then renewed by 

 a slight shower, it is probable that "wig- 

 glers" survive and complete their develop- 

 ment. 



The eggs of many of our common species resemble, superficially, 

 a little speck of soot on the top of the water, which resolves itself, 

 upon being examined by a glass, into a little skifif shaped mass, con- 

 sisting of several eggs fastened together. The eggs of Anopheles 

 niaculipennis, however, are laid separately, and are not fastened to- 

 gether, except that they naturally adhere more or less when they 

 come in contact wth each other. 



The popular belief that mosquitoes breed in grass is doubtless 

 thus accounted for. The grass is sought for shelter from heat and 



Fig. 32. Overlooked breeding 

 places. 



Fig. 33. A stickleback, fond of mosquito larvae. 



wind, and the very small depressions above alluded to, too small to 

 be observed in the grass, afiford places for egg laying. It may be 



