Page images
PDF
EPUB

and a half in length. They live together, in swarms of twenty or more individuals, in a nest made of a single leaf folded or curled at the sides, and lined with a thin web of silk. An opening is left at each end of the nest; through the lower one the dirt made by the insects falls, and through the upper one, which is next to the leaf-stalk, the caterpillars go out to feed upon the leaves near to their nests. When young they sometimes fold up one side of a leaf for a nest, and eat the other half. The stalks of the leaves, to which their nests are hung, become covered with silk from the threads carried along by the caterpillars in going over them; and these threads help to secure the nests to the branches. They eat all parts of the leaves except the stalks and larger veins, and frequently strip long shoots of their foliage in a very few days. Towards the end of September or early in October, according to the age of the different broods, they descend from the trees, disperse, and seek a shelter in crevices or under leaves and rubbish on the ground, where they make their cocoons. These are thin, irregular, silken webs, so loosely spun that the insects can be seen through them; but they are protected by their situation, or by the dead leaves and other matters under which they are made. As soon as the cocoons are finished, the insects become chrysalids, and remain quiet through the winter; and about the middle of June, or somewhat later, they are transformed to moths. They belong to the genus Clostera, or spinner, so named on account of the spinning habits of the caterpillars. The antennæ are narrowly feathered or pectinated in both sexes; the thorax has an elevated crest in the middle; the tail is tufted and turned up at the end, in the males; the fore legs are thickly covered with hairs to the end, and are stretched out before the body when the insect is at rest. Our poplar spinner may be called Clostera Americana, the American Clostera. It closely resembles the European anastomosis, from which, however, it differs essentially in its caterpillar state, and the moth presents certain characters, which, on close comparison with the European insect, will enable us to distinguish it from the latter. It is of a brownish gray color; the fore wings are faintly tinged with pale lilac, and more or less clouded with rust-red; they have an irregular row of blackish dots near the outer hind margin, and are crossed by three whitish lines, of which the first nearest the shoulders is broken and widely separated in the middle, the second divides into two branches, one of which goes straight across the wing to the inner margin, and the other passes obliquely till it meets the end of the third line, with which it forms an angle or letter V; across the middle of the hind wings there is a narrow brownish band, much more distinct beneath than above; on the top of the thorax there is an oblong chesnut-colored spot, the hairs of which rise upwards behind and form a crest. All the whitish lines on the fore wings are more or less bounded externally with rust-red. It expands from one inch and one quarter to one inch and five eighths. In Georgia this insect breeds twice a year; and the caterpillars eat the leaves of the willow as well as those of the poplar."

2. OWLET-MOTHS. (Noctue.) Our second tribe of moths, the Noctuæ of Linnæus, appears to have been thus named from Noctua, an owl, because they fly chiefly by night, and are hence called eulen, or owl-moths by the Germans. This tribe contains a very large number of thick-bodied and swift-flying moths, most of which may be distinguished by the following characters. The antennæ are long and tapering, and seldom pectinated even in the males; the tongue is long; the feelers are very distinct, and project more or less beyond the face, the two lower joints being compressed or flattened at the sides, and the last joint is slender and small; the thorax is thick, with rather prominent collar and shoulders, and is often crested on the top; the body tapers behind; the wings are always fastened together by bristles and hooks, are generally roofed, when at rest, and each of the fore wings is marked behind the middle of the front margin with two spots, one of them round and small, and the other larger and kidney-shaped. A few of them fly by day, the

See Phalana anastomosis of Smith, in Abbot's "Insects of Georgia," p. 143, pl. 72.

others only at night. Their colors are generally dull, and of some shade of gray or brown, and so extremely alike are they in their markings, that it is very difficult to describe them without the aid of figures, which cannot be expected in this treatise. The caterpillars are nearly cylindrical, for the most part naked, though some are hairy, slow in their motions, and generally provided with sixteen legs; those with fewer legs never want the hindmost pair, and never raise the end of the body when at rest. Some of them make cocoons, but the rest go into the ground to transform. Many of the Noctuas vary more or less from the characters above given, and the tribe seems to admit of being divided into several smaller groups or families, under which their peculiarities might be more distinctly pointed out. Unfortunately the history of most of our moths is still imperfectly known; and, for this reason, as well as on account of the length to which the foregoing part of this treatise has already extended, I have concluded to suppress a considerable portion of my observations on the owlet-moths and the rest of the Lepidoptera, and shall confine my remarks to a few of the most injurious species in each of the remaining tribes.

The injury done to vegetation by the caterpillars of the Noctuas, or owlet-moths, is by no means inconsiderable, and sometimes becomes very great and apparent; but most of these insects are concealed from our observation during the day-time, and come out from their retreats to feed only at night. To turn them out of their hiding-places becomes sometimes absolutely necessary, and it is only by dear-bought experience that we learn how to discover them. This is not the case with all; those of the first family, which I would call Acronyctians (ACRONYCTADÆ *), live exposed on the leaves of trees and shrubs. They have sixteen legs, are cylindrical, and more or less hairy, some of them closely resembling those of the genus Clostera, having a wart or prominence on the top of the fourth and the eleventh rings, and some of them have the

* From Acronycta, a genus of moths appearing at night-fall, as the name im

hair in tufts like Arctians and Liparians. They make tough silken cocoons, in texture almost like stiff brown paper, into which they weave the hairs of their bodies. Their moths have bristle-formed antennæ, and the thorax is not crested. Their fore wings are generally light gray with dark spots, and in many are marked with a character resembling the Greek letter y near the inner hind angle. Of those that want this character on the fore wings, the largest American species, known to me, may be called Apatela Americana, which has been mistaken for Apatela Aceris, the maple-moth of Europe. Its body and fore wings are light gray; on the latter there is a wavy, scalloped white line edged externally with black near the outer hind margin, and the usual round and kidney-shaped spots are also edged with black; the hind wings are dark gray in the male, blackish in the female, with a faintly marked black curved band and central semicircular spot; all the wings are whitish and shining beneath, with a black wavy and curved band and central semicircular spot on each; the fringes are white, scalloped, and spotted with black. It expands from two inches and a quarter to two inches and a half, or more. This kind of moth flies only at night, and makes its appearance between the middle and the end of July. The caterpillar eats the leaves of the various kinds of maple, and sometimes also those of the elm, linden, and chestnut. It is one of the largest kinds; and, early in October, when it arrives at maturity, measures from one inch and three quarters to two inches or more in length. It is of a greenish yellow color above, with the head, tail, belly, and feet black; its body is covered with long and soft yellow hairs, growing immediately from the skin; on the top of the fourth ring there are two long, slender, and erect tufts of black hairs, two more on the sixth ring, and a single pencil on the eleventh ring.f While at rest, it re

• See Phalæna Aceris, Smith, in Abbot's "Insects of Georgia,” p. 185, pl. 93.

† Those naturalists, who are familiar with the appearance of the European caterpillar of Apatela Aceris, will perceive the great and essential difference between it and that of our American Apatela, which bears about as much resemblance to the former as does that of Astasia torrefacta, of Sir J. E. Smith, an insect apparently belonging to the Notodontians, and near to Clostera and Py.

mains curled sidewise on a leaf. When about to make its cocoon it creeps into chinks of the bark, or into cracks in fences, and spins a loose, half-oval web of silk, intermixed with the hairs of its body; under this it then makes another and tougher pod of silk, thickened with fragments of bark and wood, and, when its work is done, changes to a chrysalis, in which state it remains till the following summer.

The caterpillars of the Nonagrians (NonAgriadæ *) are naked, long, slender, and tapering at each end, smooth, and generally of a faint reddish or greenish tint, with an oval, dark colored, horny spott on the top of the first and last ring. Most of them live within the stems of reeds, flags, and other water-plants; some in the stems, and even in the roots of plants remote from the water. They devour the pith and the inside of the roots, and transform in the same situations, having previously gnawed a hole from the inside of their retreat, through the side of the stem or root to the outside skin, which is left untouched, and which the moth can easily break through afterwards. The chrysalids are generally very long and cylindrical, and are blunt at the extremities. Most of the moths have very long bodies, a smooth thorax, and are of a yellowish clay or drab color; the fore wings want the usual spots, are faintly streaked and dotted with black, and have a scalloped hind margin. Those that do not live in water-plants are distinguished by brighter colors of orange-yellow and brown, with the usual spots more or less distinct on the fore wings, the margin of which is wavy; the collar is prominent, and the thorax crested. In all of them the antennæ of the males are slightly thickened with short hairs beneath.

These insects are fatal to the plants attacked, the greater part of which, however, are without value to the farmer. Indian corn must be excepted; for it often suffers severely from the

gæra. Apatela signifies deceptive; and this name was probably given to the genus because the caterpillars appear in the dress of Arctians and Liparians, but produce true owlet-moths or Noctuas.

* From Nonagria, the meaning of which is uncertain.

+ These dark horny spots are found on the first ring of most of the caterpillars that burrow in the stems of plants, or in the ground.

« PreviousContinue »