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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
months where it experienced practically all normal winter conditions 
except precipitation. 
(6) Material placed under warm, dry conditions during hibernation, 
that is with a humidity of 30 to 50 percent and a mean temperature of 
approximately 64 degrees. 
Both lots of material were placed in field cages at the time for normal 
pupation in the spring, and given as near natural conditions as possible. 
In both series the mortality was considerably above normal and the 
seasonal history throughout the year considerably delayed, in fact, the 
number of individuals completing the second generation was reduced 
to 38 per cent in the case of the larvae experiencing warm dry conditions 
during hibernation and to 75 per cent in the case of larvae experiencing 
insectary conditions. 
The treatment was continued for the second season, and the number 
of individuals completing two generations during the second growing 
season of the experiment was approximately 9 per cent in both cases. 
IV—Various combinations of drying and soaking were tried as means 
of breaking up hibernation during the winter months. All series of 
larvae were carefully weighed before and after each treatment. It was 
found that a definite amount of moisture was necessary for the main¬ 
tenance of life during hibernation and that this moisture requirement 
could not be met solely by the production of metabolic water. There 
must be a source of moisture that can come in contact with the hiberna¬ 
ting larva. 
A combination of warm, dry conditions, followed by a return to 
optimum temperature and moisture will break up hibernation as 
quickly as an exposure to low temperature with a following treatment of 
optimum temperature and moisture. However, the former method 
results in a very high mortality if the treatment is continued for any 
length of time. 
In general all indications seem to point to the rest period as probably 
the most critical period in the life of the insect, and that impresses of 
environment during this period may noticeably influence further develop¬ 
ment. 
From the present status of the work upon the relation of environment 
to seasonal history, it seems advisable to investigate thoroughly the 
activities of the insect in its originl surroundings. The practical ends 
to be gained from a general European survey are as equally desirable as 
the scientific knowledge thus made available for an accurate foundation 
for further environmental comparative study. The investigation thus 
