76 MOSQUITOES 



life of the wrig-glers may be almost indefinitely pro- 

 longed. I have watched them for twenty days, during 

 which time they did not reach full growth. The short- 

 ness of the minimum generation, however, is very signifi- 

 cant and accounts for the fact that swarms of mosquitoes 

 develop upon occasion in surface pools of rain-w^ater, 

 which may dry up entirely in the course of two weeks or 

 Jess, or in a chance bucket of water left undisturbed for 

 that length of time. 



Dr. John B. Smith has reared the species, as elsewhere 

 stated, from larvj^e found in Januarj^ frozen in ice. In 

 studying the larvae after they had been thawed out he 

 found that they remained under the water for a long 

 time, certainly fifteen minutes, and i:>robably much 

 longer. These observations thus differ radically from 

 those which I made in summer, and show that these larvae 

 must be studied still more before we know all that ma}^ 

 be found out about them. 



This species, Culex pungens, is said by Dr. H. A. Vea- 

 zie, of New Orleans, to breed most extensively in the 

 gutters in that city. The}^ are found in gutters in which 

 the water runs slowly, but more plentifully in those where 

 there is no current. In gutters that receive the refuse of 

 the gas works, tar factories, soap works, and oil establish- 

 ments, there are no larvae. They live in gutters contain- 

 ing Mississippi Eiver water, but do not prosper. Dr. 

 Yeazie thinks the fine sediment in the Mississippi water 

 blocks their breathing tubes, since they flourish well in 

 this water after it has been filtered. 



Reverting once more to the distribution of the different 



