292 
Psyche 
[December 
In the fall of 1922 and again in the fall of 1923 experiments 
consisting of corn stalks tied to stakes were set out in 20 localities 
the first year and 50 localities the second year, throughout the 
area known to be infested by this insect in New England. The 
results obtained by the examination of these experiments in the 
spring of 1923 and the spring of 1924 showed somewhat greater 
mortality during the winter of 1922-1923 than during the winter 
of 1923-1924. Winter mortality was found to be greater in 
localities farther north than in localities in the southern part of 
the infested area. Thus on Cape Cod, 5 localities averaged 0.88 
per cent of mortality in the spring of 1923 and 6 localities averaged 
1.3 per cent of mortality in the spring of 1924: In the remainder 
of the infested area in Massachusetts, 4 localities not in river 
valleys averaged 3.9 per cent of mortality, and 2 localities in 
river valleys averaged 22.6 per cent of mortality in the spring of 
1923, while 29 localities averaged 2.6 per cent of mortality in the 
spring of 1924. In the infested area of Maine and New Hamp- 
shire 3 localities averaged 33.5 per cent of mortality in the 
spring of 1923 while 12 localities averaged 9.3 per cent of mor- 
tality in the spring of 1924. 
From a study of winter weather of 15 localities representing 
the entire invested area, no one factor alone seems to be res- 
ponsible for winter mortality, but the extent of mortality seems 
to be associated with winter severity. While winter mortality 
seems to be of minor importance in the area infested by the 
European corn borer in New England at the present time, areas 
of rather high mortality have appeared, and these must play 
some part in limiting the advance and increase of the infestation 
in such localities. 
