pon those species
which, like the small social larvae, pass this season upon the earth
enveloped in a silken envelope, or, like the larvae of the Noctuellae,
between dead leaves or upon the ground itself.

On another hand, it cannot be doubted that mild winters greatly
contribute to the bringing about of a destruction of larvae and chrysalids
in two ways: First, they favor the development of mould, which, as well
known, attacks the larvae of insects when these have been enfeebled by an
excess of rain or dampness; and second, they permit beasts of prey to
continue to exercise their activity. Now, these latter are numerous.
Moles, instead of burying themselves deeply, then continue to excavate
near the surface, and shrew mice are constantly in search of food. These
small mammals, which abound in this district, destroy a large number of
chrysalids of Lepidoptera.

It is the same with birds. As soon as severe cold begins to prevail in
the north and east, they come in troops to the open fields and the
sheltered slope of the hills of our district. But it is scarcely worth
while to stop to tell of the skill and perseverance of these destroyer of
larvae. We may mention, the woodpecker, however, as a skillful searcher
for insects that lie hidden in places where the sun has melted the snow.
The carnivorous Coleoptera and the Forficulae are likewise generally in
motion during mild winters. Doubtless these last-named do not make very
large inroads in the ranks of larvae and chrysalids every day; yet, having
no other food, they destroy a goodly number of them. But I believe that
the devastations made in the army of insects by all these enemies united
do not equal those made by certain crustaceans--the wood lice.

During mild winters these pests multiply, eat, and prosper out of bounds,
and to such a point that, in a climate like ours, they become a true
scourge that prevails everywhere, out of doors and within. Once in a
place, they begin to look for larvae and chrysalids, which they devour.
The severe cold seems to have destroyed a certain number of them, since
they are now not so numerous by far; and it has at least certainly put a
stop to their devastations at an epoch when the larvae are more
particularly exposed to the attacks of their enemies. It is to this
cause, as well as to the preceding, that I am led to attribute the
extraordinary multiplication of so many species during the three last
summers, which were separated by