DIPTERA OF MINNESOTA. 



45 



too, that our mosquito, as does the salt marsh mosquito, lays its eggs 

 in mud or elsewhere, where its instinct tells it water will come later. 



Every one is familiar with "wigglers," which are the larvae of 

 mosquitoes, changing their appearance to become pupae, in which 

 condition they exist for a short time before issuing from the water 

 as perfect flies. Our illustrations show these stages, as also the 

 appearance of the eggs. In a general way we may say the egg stage 

 lasts from ten to twenty-four hours, the life of the "wiggler" from 

 seven to ten days, sometimes longer, the pupal stage ordinarily from 

 two to three days, sometimes longer, and the adult's life on an average, 

 under natural conditions, probably from eight to twelve days. This 

 statement is only a general one, since climatic conditions probably 

 have great influence on duration of life. Mosquitoes have been 

 kept alive in captivity for three weeks. Consideration of the above 

 data shows that the duration of one generation is naturally, in round 

 numbers, from i/^^ to 26 days. Turning to the individual species, 

 we can speak more in detail : 



Egg. 



Anopheles 



7naculifennis i to 4 days 



C. fipiens 20 hours 



C. pungens 1 10 to 12 hrs. 



lyarvae. 



16 days 



2 to 4 wks. 



7 to 8 days. 



Pupae. 



4 to 5 ds. 

 2 to 8 ds. 

 2 days. 



Total time required 

 from laying of egg 

 to emergence from 

 pupal stage. 



21 to 25 

 17 to 37 

 9/4 to \oYi 



days 



To show the enormous number of mosquitoes which may be found 

 in a comparatively small amount of water, we quote from an experi- 

 ment made by Dr. Lugger in 1896. By a careful estimate he found 

 that one rainwater barrel contained 17,259 eggs, larvae and pupae, 

 and in another barrel he found 19,110 eggs, larvae and pupae. 



A curious person at once asks, "Well, where do they come from 

 in the spring ; does not the winter kill them all off ?", and the answer 

 is that many impregnated adult females hibernate, passing the win- 

 ter under boards, under moss, in cellars and in garrets, in crevices of 

 various sorts, in the woods, about the barns and out-buildings. They 

 are often found in curtain hangings and in draperies indoors. These 

 are sufficient to start them in the spring, and their rapid rate of in- 

 crease does the rest. Even "wigglers" frozen solid in the ice in 



