386 



THE GYPSY MOTH. 



when brought in molted before these eggs hatched, passed 

 all its transformations, and the moth emerged from it in 

 good condition. 



In July, 1895, a careful examination was made to deter- 

 mine the proportion of caterpillars in the field that had the 

 eggs of the Dipterous parasites attached to them. July 3, 

 five trees were examined in Dorchester, and 2,200 cater- 

 pillars were found, 500 of which had the eggs of parasites 

 on them. July 8, six trees were examined in Medford, and 

 1,847 caterpillars found, 397 of which bore parasite eggs. 

 The total number of caterpillars examined was 5,547, of 

 which 1,597, or nearly 29 per cent., had the eggs of Dip- 

 terous parasites attached to some part of the body. 



Several Dipterous parasites were bred, during the summer 

 of 1895, from infested pupae, the majority of which pro- 

 duced only one' parasitic fly, while a few produced two. 

 Many parasitized pupse contain maggots which have not yet 

 pupated. The vitality of these Dipterous parasitic larvae is 

 very remarkable. One of them was placed in a twenty per 

 cent, solution of formol at night, August 15, and twenty- 

 four hours later it was found swimming around, apparently 

 uninjured. The larva was at once removed from its formol 

 *'bath," and was still living October 1, but had not pupated. 

 In several cases where two larvae were found in a small pupa 

 of the gypsy moth, and there seemed an insufficient amount 

 of food for them, a large female pupa was cut open and a 

 parasite larva placed on the cut end of each half. They at 

 once burrowed into the tissues and fed there several days. 

 One larva ate the substance of six female pupae in this way 

 before reaching its full growth. 



Fifty gypsy moth caterpillars, having eggs of a Dipterous 

 parasite on them, were collected in Dorchester, June 21, 

 1895, and carefully bred in separate boxes. The eggs were 

 deposited without regularity on nearly every part of the 

 body. Forty-three of these caterpillars passed their trans- 

 formations, producing perfect moths, six males and thirty- 

 seven females ; while seven died, but not because of the 

 parasites, for the caterpillars had all molted before the eggs 

 of the parasite had hatched. Two hundred and fifty-two 



