PARASITE, APHIDIUS TESTACEIPES. 107 
the second molt will become adult, but ma}' 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. 
