26 



in view vof the care with wliieh the figures accompanying this article 

 have been drawn. The air tubes no longer open at the anal end of the 

 body, but through two trumpet-shaped sclerites on the thorax, from 

 which it results that the pupa remains upright at the surface, instead 

 of with the head downward. rhere is a very apparent object in this 

 reversal of the position of the body, since the adult insect issues from 

 the thorax and needs the floating skin to support itself while its wings 

 are expanding. 



In general, the adult insects issue from the pupa^ that arc two days 



Fig. 3. — Culex jiunyais : Full-grovvu larva at left, pupa at right — uiilarged (original). 



old. This gives what is probably the minimum generation for this 

 species as ten days, namely, sixteen to twenty-four hours for the egg, 

 seven days for the larva, and two days for the pupa. The individuals 

 emerging on the first day were invariably males. On the second day 

 the great majority were males, but there were also a few females. The 

 preponderance of males continued to hold for three days; later the 

 females were in the majority. In confinement the males died quickly; 

 several lived for four days, but none for more than that period. The 

 females, however, lived for a much longer time. Some were kept alive 



