MOSQUITOES IN GENERAL 39 



for the species. However, it may be said with cer- 

 tainty that all the species pass through a complex 

 metamorphosis represented by the usual stages, egg y 

 larva, pupa, and adult (Fig. 20). The larvae are com- 

 monly called "wrigglers" and the pupae "tumblers." 

 Water in which to pass the early stages is absolutely 

 essential. The eggs may be deposited on wet mud and 

 the larvae may exist for some hours in similar situations. 

 The experiments recorded by Dr. Howard are of con- 

 siderable interest, and he reports thus : — 



" In no case, however, were we able to revive larvae 

 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 larvae revived." 



The eggs of mosquitoes are deposited from early 

 spring to early autumn, and in warmer parts of the 

 country active " wrigglers " may be found throughout 

 the year. The writer has found nearly full-grown larvae 

 in parts of California in January and pupae from which 

 occasional adults emerged during the month of Febru- 

 ary. These overwintering larvae are quite certainly from 

 eggs deposited late in the autumn, and the growth is 

 comparatively slow. The adult mosquitoes which 

 make their appearance the earliest in the spring are, as 

 a rule, individuals which have been in hibernation 

 during the winter. Probably about ten days is the 

 shortest time required for any of the commoner species 

 of mosquitoes to pass through the various stages. 

 Howard gives the time for Culex pungens as " sixteen 



