the larger weevil. Like them, they enter the ground and pass the
first winter unchanged. The grub stage is continued throughout the
summer, but late in autumn, after the beetles of the larger species have
been on the trees for some weeks and deposited most of their eggs, the
larvae of the smaller species transform to adults. Instead of coming
from the ground, however, they remain in their earthen cells throughout
the winter. The next spring, prior to the blooming of the
chestnut-trees, they emerge from the ground and soon thereafter collect
in large numbers on the male catkins of the chestnuts. At this time very
little feeding is done and the sex instinct does not manifest itself. As
the time approaches for the nuts to mature, however, the beetles begin
to feed and pair and soon thereafter to lay their eggs in the ripening
nuts. Most of the eggs are deposited directly into the nuts after the
burs begin to open. In the case of the larger weevils the beetles are
present only about three months of the year. Those of the lesser
species, however, are perpetually present, those of the younger
generation reaching the adult stage in the ground before those of the
previous generation have finished laying their eggs in the ripening
nuts. As with the larger species, a few of the smaller weevils carry as
larvae for several years to tide over possible failures of the chestnut
crop. The life cycle of the hickory-nut weevil is similar to that of the
larger chestnut-weevil, and that of the hazel-nut weevil is like that of
the lesser chestnut weevil. Both cycles are represented among the
acorn-infesting species.
Any intelligent warfare against the nut weevils calls for a knowledge of
these distinctive life histories. Thus, an abundance of maturing larvae
of the larger species this autumn will insure an abundance of beetles to
deposit eggs in the nuts next autumn. With the lesser weevil, however,
maturing larvae this autumn will not affect the number of beetles on the
trees the succeeding autumn but will provide beetles for the crop two
years hence. Large numbers of beetles of the lesser species may be
destroyed by collecting them from the blossoms of chestnut, but, at that
season of the year there are no beetles of the larger species abroad.
These weevils are to be made the subject of a bulletin by the Bureau of
Entomology in the near future, in which it is hoped to go more fully
into a discussion of control measures.
_Walnut Hus
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