458 Journal of Agricultural Research voi. vi, no. 12 



I : 



the average of 33.6 square inches eaten by 20 nonparasitized larvae dur- 

 ing the same stages. Larv^ae 19, 22, 23, 24, and 25 were partially de- 

 veloped fourth-stage specimens when oviposited in, and they ate, during 

 the remainder of their life, which lasted until the parasites emerged from 

 them some time during the last or sixth stage, 20.63, 17-36, 21.41, 17.64, 

 and 17.99 square inches of corn leaf, respectively, as compared with the 

 average of ;54-77 square inches eaten by 20 nonparasitized larvae during 

 the last three stages. (See Table I.) 



From these results it will be seen that parasitized larv^ae ate approxi- 

 mately half as much as unparasitized larvae during the same periods, 

 and it seems conclusive, even from these few records, that parasitism by 

 A. viilitaris is directly beneficial in the generation attacked. From the 

 results obtained it might seem as though larvae oviposited in at an earlier 

 date would eat more before being killed, but the time spent in the host 

 by the parasites seems to be fairly constant, and this was also noticed in 

 a larger number of cases in former experiments with A . militaris. Hence, 

 it is believed that in such cases the larvae would have only approxi- 

 mately the same amount of time for feeding, and a larger portion of this 

 period would occur during the earlier stages, when a much smaller 

 amount of food is eaten, so that the amount eaten would be less than 

 the normal for unparasitized lar\'-ae. 



