GYPSY AND BROWN-TAIL MOTHS. 23 



than it was in the case of the gypsy moth, owing to the greater 

 dispersive powers of nearly all of the parasites. With one 

 exception, they more nearly resemble the brown-tail moth in 

 this respect, being gifted with the power of flight; and, as is 

 well known, the territory covered by this insect is much more 

 extensive than that covered by the gypsy moth, although the 

 latter was introduced into America more than twenty years 

 earlier. 



Another enormous step in advance, which has marked the 

 progress of the work the present season, is the accumulation 

 of certain valuable data which throw much-needed light upon 

 the subject of parasite dispersion, and which have tended more 

 than anything which has come about since the earliest beginning 

 to encourage those who have been charged with direction of 

 the work. For the first time it is possible to calculate, with 

 some foundation upon fact, the probable outcome of the under- 

 taking. It is difficult to do this on the small amount of abso- 

 lutely authentic information at hand, and to vouch for the 

 accuracy of the conclusions with any degree of assurance; but 

 the attempt has been made, and will appear in the concluding 

 paragraphs. 



First, in order to make more clear the ground which supports 

 these conclusions, a brief account of each of the introduced 

 parasites of the gypsy moth will be given. No attempts have 

 been made to go into technical detail concerning the lives and 

 habits of these several species, further than is necessary to give 

 a general idea of their methods of attack, and of the hopes and 

 fears which are felt for the future of each. 



Paeasites of the Egg. 

 Anastatus bifasciatus. 

 This minute parasite (Fig. 1) attacks the newly deposited 

 eggs of the gypsy moth during the brief interval which elapses 

 before the embryonic caterpillars develop. Its eggs (Fig. 2) 

 are deposited singly, one in each individual egg of the host, and 

 its larvae feed upon the substance of the host eggs and become 

 full fed in about three weeks. They then enter on a long rest- 

 ing stage, snugly ensconced within the limited confines of the 



