MOSQUITOES IN GENERAL 9 



was dark in color, owing- to the drainage from a manure- 

 pile near by, and when glanced at casually showed no 

 signs of life ; but on dipping in a coffee-strainer it was 

 found to be literally massed Avith nearly full grown mos- 

 quito larvae, many hundreds of which had been brought 

 together into this restricted place. Drying continued 

 iTutil there was almost no water left, but before the larvae 

 died, that is to say, about twenty-four hours after the 

 water contents were estimated at from three to four cubic 

 inches, there came a heavy rainstorm which filled the 

 pond with water, after which it was seen to contain ap- 

 parently its usual stock of mosquito larvae. From this 

 observation we are able to estimate the usual happenings 

 in a mosquito pool. As the water dries the larvae grad- 

 ually retire to the deepest point, and after the pool is 

 apparently dried up there is still enough moisture at 

 this deepest point to keep the larvae alive a number of 

 hours. That they may die, and that, as I believe, they 

 invariably do die in the absence of all moisture and in a 

 space of time which must be reckoned by hours and not 

 by days, is evidenced by the laboratory observations 

 mentioned above. 



Length of Life of Adult Mosquitoes. 



It is very difficult, in fact practically impossible, to 

 estimate the normal length of life of the adult of any 

 species of insect that flies. We may keep them in con- 

 finement and count the few days of their life, but the 

 conditions are abnormal and cannot be made perfectly 



