AMERICAN TENT CATERPILLAR 



63 



soon after coming out of the egg there were heavy and long 

 continued rains. As a result a large proportion of the young 

 caterpillars were washed away and killed. In general, those 

 only survived that were able to shelter themselves on the 

 under surface of the twig to which the egg mass was attached. 

 '^Consequently/^ as I wrote in last year's report, "at the begin- 

 ning of the season of 1898 there was a considerable reduction 

 in the numbers of the caterpillars. The survivors, however. 



Fig. 1'). American Tent Caterpillars killed by disease. 



developed in sufficient abundance to be decidedly in evidence 

 in May, but during the last weeks of their growth there ap- 

 peared among them a bacterial disease, a sort of insect cholera, 

 which killed them in vast numbers. The effectiveness of this 

 disease was doubtless increased by the wet weather prevailing 

 at the time. Early in June nearly every nest was full of the 

 dead and dying caterpillars, those upon the outside of the web 

 hanging limp and lifeless at first (Fig. 15), and then gradually 

 shriveling up until only the dried skins told of their presence 



