56 



that they are by no means in the same large proportion to the 

 male moths as in localities where the disease has not occurred 

 among the caterpillars. The effective result, then, will be shown 

 at the time of oviposition, in the decrease of the number and 

 size of the fresh clusters, compared with those of the previous 

 year. To be sure, this will not always be the case ; for instance, 

 in localities in which Flacherie appears very late. However, 

 places infected early enough, always show as a result a diminu- 

 tion in the number of the fresh clusters, sometimes to 100 per 

 cent. The reduced average size of the clusters also has a close 

 connection with the wilt. Heretofore it has often, but errone- 

 ously, been supposed that small clusters were deposited by 

 small female moths, which suffered during their caterpillar 

 stages from lack of food. Certainly such cases are not rare, 

 but the origin of small clusters is capable of yet another ex- 

 planation. For instance, in localities in which there are few 

 gypsy moth caterpillars, and where there is no lack of food, but 

 where the wilt has worked, egg clusters are found which are no 

 larger than' a pea or a bean. Such clusters contain from 4 to 12 

 eggs, with embryos which are usually incompletely or not at all 

 developed. In such localities it may often be recognized, from 

 the volume of the abdomen, even of the freshly emerged female 

 moths, which were little below the normal size, that the body 

 contained only a small number of eggs. Also, in several cases 

 the interior of the body was examined, and then it was found 

 that the cause of the small circumference of the body was that 

 the ovary was small. Females which had already oviposited and 

 died were examined to see whether they contained more eggs in 

 their bodies. Eggs were always found in females that had laid 

 egg clusters which were only partly, or not at all, covered with 

 hair. But there were sometimes found undeposited eggs in fe- 

 males which had completely covered the cluster with their ab- 

 dominal hairs. All this must be taken in connection with the 

 wilt, for female moths from healthy colonies deposit all the eggs 

 they contain, as long as they are not interrupted at the time of 

 egg laying, and it does not matter whether the individuals are 

 large or small. 



The most important point to be noticed is the fact that the 



