DISEASE IN CONTROL OF MOTHS. 99 



later practically every caterpillar was destroyed in one particular 

 locality which had been selected as a good place for the very first 

 colony of Apanteles fulvipes, there seemed to be reason to hope for 

 speedy relief through disease. About this time these hopes were 

 rudely shattered by the failure of several attempts to demonstrate 

 the infectious or contagious nature of the disease through experi- 

 ments carried on at the laboratory. Its noncontagious nature was 

 further indicated by the fact that it did not spread across a narrow 

 roadway near the laboratory, one side of which was swarming with 

 dying caterpillars, while the other was peopled with an alarming 

 but not destructive abundance of healthy ones. It appeared, after 

 all, as though the views often expressed by Mr. A. H. Kirkland (at 

 that time superintendent of the moth work in Massachusetts) to the 

 effect that the disease was nothing more than the natural concomi- 

 tant of overpopulation, and that an insufficient or unsuitable food 

 supply was the true explanation of its prevalence, were right. That 

 it was not to be depended upon for immediate results was certain 

 when, at the close of 1908, a further alarming and apparently an 

 unaffected increase in the distribution and abundance of the gipsy 

 moth in Massachusetts and New Hampshire was found to have taken 

 place wherever conditions were not such as to render destruction 

 through disease the only thing which saved the gipsy moth from 

 extinction through starvation, or where active hand suppression work 

 had not been undertaken. 



In 1909, and again in 1910, observations upon the progress of the 

 disease were made almost daily throughout the caterpillar season. 

 It was no longer looked upon as a serious obstacle to the success of 

 the parasite work, except as it interfered (as it frequently did most 

 seriously) with the work of colonizing Anastatus, and to a lesser 

 extent Calosoma. It was also, as ever, the cause of serious trouble 

 whenever attempts were made to feed caterpillars in the laboratory 

 in confinement. 



The disease acquired new interest, however, through the gradual 

 accumulation of evidence tending to support the theory that it was 

 either transmissible from one generation to another through the egg 

 or that a tendency to contract it was thus transmitted. 



Recognition of this characteristic through cumulative evidence 

 resulting from more occasional or specific observations than it would 

 be possible to review at this time, was accompanied by the almost 

 equally apparent fact that the disease was becoming slightly more 

 effective at a somewhat earlier stage in the progress of a colony of 

 the gipsy moth following its establishment in a new locality. It 

 was found, for example, in New Hampshire in colonies which had 

 barely reached the stripping stage. A few years before the cater- 

 pillars composing such colonies would naturally have migrated from 



