368 



THE GYPSY MOTH. 



shrivelled, and the clusters partly washed away by the rains. 

 From these as well as other observations made this season 

 it seems more than probable that a female gypsy moth that 

 has not mated does not make a perfect egg-mass, and that 

 an experienced observer may distinguish in most cases an 

 egg-cluster that is infertile from one that is fertile. 



IN-AND-IN BREEDING. 



A cluster of eggs laid by one female gypsy moth was 

 placed in a breeding cage in the spring of 1893, to deter- 

 mine whether the two sexes would emerge at the same time, 

 mate and lay fertile eggs. This was for the purpose of 

 ascertaining whether it would be possible for a fertile 

 female, if transported to a new region, to lay eggs capable 

 of establishing a new colony ; or, if a single cluster of eggs 

 should be carried outside of the infested region, whether a 

 new colony would result. The eggs used in this experi- 

 ment commenced hatching May 5, 1893, and the caterpillars 

 were fed on apple leaves till they reached maturity, when 

 they pupated. The moths emerged as indicated in the fol- 

 lowing table : 



In all there were 478 moths, 267 males and 211 females, 

 which mated as readily as those from different egg-clusters ; 

 and, as their eggs proved fertile, there is every reason to 

 believe that, under favorable circumstances, this cluster of 

 eggs could have established a colony of moths. See " The 

 Entomologist," Vol. XIX, page 281 (1886). 



INTERNAL ANATOMY. 



The following description of the internal anatomy of the 

 different stages of the gypsy moth was prepared by Mr. A. 

 H. Kirkland. 



