PARASITE, APHIDIUS TESTACEIPES. 107 



the second molt will become adult, but may be either winged or 

 wingless; the wings in such cases often being imperfect. Oftentimes 

 parasitized aphidids reach the third molt, but do not become adult 

 before death, though the parasite reaches maturity, and it is probable 

 that such Toxoptera were parasitized just before casting the second 

 molt. This may also account for some of the small individuals among 

 the parasites. 



EFFECT OF PARASITISM BY APHIDIUS UPON FECUNDITY OF HOST. 



Experiments have been conducted with the view of learning the 

 number of young that may be produced after parasitization. This 

 can probably be best illustrated by Table XII. 



