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 
