April, '11] 



LOHRENZ: WOOLLY APHIS 



169 



quite inactive. After passing through the last molt, the male becomes 

 quite lively and runs about in search of females, which do not move 

 about in the latter part of their life, but are fertilized and lay their 

 egg at the place where they spend the greater part of their hfe. 



DATA FROM ISOLATED APHIDS 



Two true sex forms, male and female, which were produced on 

 November 26, had molted for the fourth time on December 8, probably 

 before that time. They were confined to close quarters in a test tube, 

 and after a few hours were seen to mate. On the following day, 

 December 9, the female deposited her egg. The egg is of brown color, 

 and about twice as long as wide. After oviposition the female looked 

 quite shriveled up, yet lived several hours. The mating of this pair 

 had probably not been successful, since the egg retained its brown 

 color. 



As seen from the above table, I did not succeed in getting more than 

 four young from a winged female. Other investigators say, however, 



3 



