THE MALARIAL MOSQUITOES 107 



stead of from the anal end of the abdomen, will at once 

 be noticed. The pupa of Anopheles is quite as active, 

 when disturbed, as is that of Culex. If one touches the 

 surface of the water near it with the fing-er, the pupa at 

 once wriggles violently away, returning shortly to the 

 surface for air. 



The duration of the pupal stage in Anopheles varies 

 according to the weather. Five days was the minimum 

 observed during June, although several specimens re- 

 mained in this stage for ten days. The adults issue as 

 do those of Culex. 



The entire life round, therefore, of Anopheles viaculi- 

 pcnnis in the generation studied by the writer is as follows : 

 egg stage, three days ; larval stage, sixteen days ; pupal 

 stage, five days ; making a total period in the early stages 

 of twenty-four days. It should be stated, however, that 

 during the early larval existence, toward the end of May 

 there occurred nearly a week of cool weather, so that it is 

 certain that in the hot season in July and August the 

 growth and transformations will be more rapid. It will be 

 remembered that the writer traced Culex pungens through 

 an entire generation in the latter part of June, in ten days. 



European Observations on the Same Species. 



Nuttall and Shipley state that when the eggs are first de- 

 posited they are white, but that they soon blacken. They 

 are boat-shaped, and one end is slightlj^ deeper and fuller 

 than the other. The thickening at the edge, which in pre- 

 vious paragraphs was called the clasping membrane, is 



