184 PARASITES OF GIPSY AND BROWN-TAlL MOTHS. 



In the course of the first unavoidable experiment in partheno- 

 genesis the attempt was made to secure the fertilization of the female 

 through union with her own asexually produced offspring, but, 

 although she lived after they had completed their transformations, no 

 results were secured. It seemed to be within the bounds of possi- 

 bility that success would follow if the experiment were differently 

 conducted, and accordingly in the fall of 1909 Mr. Smith repeated 

 it, with this variation, that the females, after they had deposited a 

 few eggs, were rendered dormant by exposure to moderate cold, 

 awaiting the issuance of their progeny. This time no difficulty was 

 experienced. The parthenogene tic ally produced males mated freely 

 with their respective parents, and the subsequent progeny in each 

 of several instances consisted of both sexes. 



Females thus reared were mated with their brothers (which were 

 at the same time their nephews), reproduced with the ordinary 

 freedom, and their progeny were of both sexes in the usual proportions. 

 Still another generation showed no signs of weakness or any sort of 

 abnormality, and the experiment was discontinued. 



In sexual reproduction the males appear always to be largely out- 

 numbered by the females. Nothing like the diversity in this respect 

 which has been noted in the case of other chalcidids has been observed 

 in the case of Schedius. 



REARING AND COLONIZATION. 



When the first individuals of Schedius were secured from the 

 imported Japanese egg masses in April, 1909, there was no difficulty 

 in securing reproduction upon gipsy-moth eggs collected in the open, 

 but by the time the second generation was secured those which had 

 remained in the open were about to hatch, and would hatch almost 

 immediately they were brought indoors. A large quantity of eggs 

 had been placed in cold storage in anticipation of this, and it was 

 found that these would hatch nearly as quickly when they were 

 removed. Oviposition at any time within a few hours of the time 

 when the eggs would otherwise hatch was generally successful, but 

 when the eggs hatched within 36 hours after being exposed to the 

 degree of warmth necessary to secure oviposition of the parasite, it 

 soon became evident that not very much increase was to be expected. 

 Accordingly, the experiment was made of killing the host eggs through 

 exposure to just enough heat to bring this about. The parasites ovi- 

 posited in these dead eggs with the same freedom that they would 

 attack the living, and reproduction ensued. The progeny, however, 

 were small and weak, and not as prolific as those secured earlier in 

 the spring. 



Thus, in one way and another the species was carried through the 

 summer, and with the deposition of fresh gipsy-moth eggs early in 

 July much better results were secured, and the parasites immediately 



