During the Winter months, when our trees and shrubs are leafless these curious silky structures are readily seen, and are found on many different trees and shrubs, but perhaps oftener on the twigs of apple trees and currant bushes than anywhere else. They are the cocoons of a very large and beautiful moth, called the Cecropia moth, (Attacus Cecropia,) which thus spends the winter in a quiet and torpid condition.
If you cut a twig on which one of these cocoons has been hung, and shake it, you will feel that it contains a heavy body which is to some extent moveable, and you can feel a slight dull thud as it falls from side to side. This winter home of the insect is about three inches long, shaped something like a pod, tapering towards each end, and invariably fastened lengthwise to the twig. It is of a dirty brown colour; the exterior is very close and papery like, although much wrinkled, and is quite impervious to wet. Let us look inside of it; underneath the close exterior we find a mass of loosely woven threads of strong yellow silk which surround the dark brown chrysalis and fill the intervening space, the upper end of the cocoon where the moth is eventually to make its escape, being much looser in texture than the other portions. The chrysalis itself, the object of all this care, is smooth, of a dull brown colour, and about one and a half inches long, and 5/8 of an inch broad in the widest portion.
Early in June—or if the cocoon is kept in a warm room, many weeks before this—a marvellously beautiful moth issues from this snug enclosure. When the time has come for its escape, the shelly structure of its prison house is rent, split open along the back, and at once restless movements begin within; the struggling creature as it tries to free itself, making a scratching noise as it tears away the silken bars which stand between it and the outer world, and this noise can be distinctly heard at some distance from the object. At this juncture a fluid is secreted from the mouth of the insect which so softens the silk as to make the escape of the moth a comparatively easy matter, while without this wise provision it might remain in its cell and exhaust itself in fruitless efforts to get out. Presently the fore legs appear, thrust out of the upper end of the cocoon, then the head crowned with its beautiful feather-like antennæ; and very soon a heavy looking object with a large plump body and soft clumsy little wings is drawn slowly out of the orifice, and stands before you in the free air.
The first care of the moth is to place itself in such a position that its wings may hang downwards, the only favourable posture for their proper development, then a rapid process of growth or expansion begins, resulting in full maturity in about half an hour, during which time the wings enlarge from the size of an ordinary bumble bee until they measure from five to six inches across.
This magnificent creature is nicely represented in Fig. 2. Both front and hind wings are of a rich brown; the anterior pair greyish, shaded with red, while the posterior are more uniformly brown; about the middle of each of the wings there is a nearly kidney-shaped white spot, shaded more or less with red, and margined with black. A wavy dull red band crosses each of the wings, bordered within on the front wings, more or less faintly with white, while on the hind pair the band is widely and clearly margined with the same colour. The outer edges of the wings are of a pale silky brown, in which, on the anterior pair, runs an irregular black line which on the hind wings is replaced by a narrow, double broken band of the same hue. The front wings next to the shoulders are dull red with a curved white and black band, varying in distinctness in different specimens, and near their tips there is an eye-like black spot with a bluish-white crescent. The upper side of the body and the legs are dull red, with a wide band behind the head, and the hinder edges of the rings of the abdomen white; the under side of the body is also irregularly marked with white. Below, the wings are very much like the upper surface, but paler.
FIG. 2.
These gay creatures are nocturnal in their habits, flying like bats in the dim twilight and dusky night. After pairing, the female deposits her eggs, numbering 200 or more, a process which occupies some time, as the eggs are not laid in patches, but fastened singly with a glutinous material, usually on the under side of a leaf. The eggs are about one-tenth of an inch long, nearly round, of a dull creamy white colour, with a reddish spot near the centre. They usually hatch in about a week or ten days.
The subsequent history of this curious and beautiful insect will be given hereafter.
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