The Caterpillar of this Moth is one of the kind called loopers, and is very destructive. The chrysalis is naked and shining; and its colour is a bright yellow with black bands. The Moth is white, spotted with black, and hence its name of Magpie.
The black and white caterpillar of this Moth is very destructive to currant and gooseberry bushes, and in some seasons particularly so. Mr. Kirby especially cites the devastations at Hull in the spring of 1814. He also confirms Boerhaave’s assertion, that the severity of winter has no effect in destroying the larvæ of those insects, as these abounded even more after a winter when Fahrenheit’s thermometer stood at zero, than after a winter which was remarkably mild.
THE WINTER MOTH.
(Geometra, or Cheimatobia brumata.)
The Caterpillar delights in newly-opened leaves; it is not so ravenous as many others, making long intervals between its meals, but it seldom quits a leaf until it has entirely consumed it. The colour is very elegant. The upper part of the body is of a fine yellowish green; but it is by no means so beautiful after as before feeding, its skin being so thin as to transmit the hue of whatever food it eats. They are also called looper Caterpillars, because when they crawl they draw their hind and fore feet together, so as to form their bodies into a loop. They go into the pupa state towards the end of June, burying themselves for that purpose in the earth; and in November or December the perfect insect is brought forth.
It is evident that they possess great muscular power, and hence their positions during repose are very striking. Fixing themselves by their hinder feet alone, they extend their bodies in a straight line, holding it in that position for a long time. This, together with their obscure colours, and the warts on their bodies, render it often difficult to distinguish them from the twigs of the trees on which they feed. When alarmed, these Caterpillars have the instinct to drop from the leaves, and suspend themselves by a thread, which enables them to remount when the danger is over.