us, or rather were confined
to certain circumscribed limits. Thus, the Noctuellae, with the exception
of a few species abundant everywhere, were almost wanting, and I know of
no other country where the dearth of common species of nocturnal
butterflies was so great. But during the winter of 1878 there supervened
a radical change. Persistent winds from the northwest, driving back the
currents of warm air from the south, brought on an intense cold that
froze everything; or, when some variation occurred in them, clouds formed
and dissolved into a rain that immediately froze, so that the large roads
remained for weeks covered with a layer of rime from two to four inches
thick.

[Illustration: GREEN WOODPECKER SEARCHING FOR INSECTS.]

The winters of 1879 and 1880 were equally cold; we may even say that the
latter was the severest that had been experienced in fifty years. This
year the sea-sand, along with the ice and snow, formed a thick crust all
along the tide-line--this being something rarely seen along our coast.
The first of these three winters (1878-1879) killed all the arborescent
veronicas and a few sumacs. As for the fuchsias and myrtles, they were
frozen down to the level of the soil.

I now come to the effects of this severe cold upon the insects.

The Lepidoptera, which before were rare, became more and more common in
1879, 1880, and 1881, and so much so that during the last named year they
abounded; and species that had formerly been detected only at certain
favored points spread over the entire coast and into the interior of the
country. The geometers appeared in numbers that were unheard of. But this
change was especially striking as regards the Noctuellae, in view of the
previous rarity of the individuals belonging to this family.

We have here an example of the direct relation of cause to effect,
although I am not in a position to assert that the effect is always
produced in the same way. To me there is no question as to the fact that
the constitution of those insects which nature has accorded the faculty
of liberating is strengthened, and that their chances of life are
increased, if the cold of winter is intense enough to plunge them into an
absolute rest, and is not unseasonably affected by warm, spring-like
days. It is certain that such cold is capable of contributing largely to
the multiplication of the individuals of such species as hibernate in the
egg state, and it also has a beneficent influence u