8 MOSQUITOES 



scale in g'l'iss vessels have shown that the larva; of Culex 

 ■will exist for some little time in wet mud and tliat some 

 of them will successfully transform after w atci- has been 

 added, but in no case were we able to revive larva' in 

 mud from which the water had been drawn off for more 

 than forty-eight hours, and after twenty-four hours only 

 a small proportion of the larva; revived. These results 

 accord very accuratel}' with those reached by English 

 observers in Africa, and, in fact, accurate ol)servations 

 have not carried the larvne out of water alive for more 

 than forty-eight hours. The im]iression to the contrary 

 has probably been gained from oljservations on })ools 

 which in reality did not entirely diy u]). Mr. V. A. 

 Sperry, of Chicago, has made observations upon a j^oud 

 which dried up and in which he could find no dead larvae, 

 but he writes that after a week it rained and as soon as 

 the rain stopped he found the mosquito larvae all through 

 the water as lively as ever, and they began to issue as 

 adults in about a week from that time. Mr. Benjamin S. 

 Pascal, of Newfield, N. J., has sent to me an account <»f 

 observations of his own which indicate to him tliat mos- 

 quitoes may breed in grass or moist eaith. 



In the summer of 1900, I watched a slowly evaporating 

 pool with great interest. It contained a surface area of 

 about twenty -four square feet, and was fed entirely l)y 

 rain-water and surface drainage. It was well stocked 

 with mosquito larva^, and after a long drought the Avater 

 was observed to have evaporated almost entirely, only a 

 small i)uddle remaining in tln^ centre, wliich contained at 

 the outside only three or four cubic inches of water. It 



