rains, the hairs are carefully placed in a sloping direction, like the tiles on a house, or the nap of a well-brushed hat, pointing downwards, towards the base of the cone. The eggs, which are deposited with so much care, are destined to abide all the pitiless pelting of the storms of winter; for, although they are laid in the beginning of harvest, they are not hatched till the elm, which is to furnish food to the future caterpillar, comes into leaf in the following spring. This covering of down, from the manner in which it is tiled and brushed smooth by the mother moth, not only protects them from wet, but, being one of the best non-conductors, keeps them safe from the injury which they might sustain from severe cold, or, what might be more fatal, from sudden alternations of heat and cold.

In the instance now detailed, there are some things worthy of particular notice; and, as it is a fair specimen of the wonderful instincts of insects with reference to the preservation of the species during winter, it may be proper to make a few remarks on the subject. Let it be observed, first, that in the previous states of the insect, whether as a caterpillar or a chrysalis, it had no power of continuing its species. It is not till its last and most perfect stage that this faculty is bestowed; and it enters on that stage just in time to flutter awhile in the sunshine, and then to die before the cold of the waning year interrupts its enjoyments, withers the vegetables on which it feeds, and chills its delicate frame; and in time, too, to lay its eggs, that they may weather the coming storms of winter, which the parent could not endure, and be hatched when the breezes of spring begin to breathe softly, and Nature again proceeds to scatter her stores of food. It cannot be here said, either that the insect dies from the inclemency of the season, or that the hatching of the eggs is retarded by the deficiency of warmth; for the season is still genial, when the former, having fulfilled the intentions of Nature, ceases to exist, and months of weather not inferior to the heat of spring, succeed the depositing of the latter. It is no other than a wise Providential arrangement.

Another surprising feature of the instinct displayed by this moth, (which, however, so far from being peculiar to the species, is only an instance of the general faculty affecting almost the whole insect creation,) is the choice of the spot where she deposits her eggs. These eggs, when hatched, are destined to produce caterpillars, whose peculiar food is to be found in the leaves of the oak or elm. From all the trees of the forest, she, therefore, selects one or other of these as the place for depositing her precious gift to a future year, although it is not from them that her own means of subsistence are to be gathered; and although, so far as we are able to judge, there is nothing in her condition, as a moth, which could lead to the preference.

We have already spoken of the remarkable manner in which the gipsy-moth protects her eggs from the weather; but it may be proper to make an observation or two on the eggs, themselves, applicable generally to all insect eggs, which are exposed to the storms of winter. The glutinous matter by which the eggs are united, when protruded from the insect, and which is so necessary for preserving them in a mass, and for fixing them to the spot, is found, contrary to the nature of many similar substances, to be insoluble in water, and therefore incapable of being affected by the copious rains to which they are destined to be exposed. But this is not so remarkable as another fact, which has been proved by some severe tests, and which shows how admirably the constitution of these eggs is adapted to the season of winter. Both Spallanzani and Hunter made experiments to ascertain the degree of cold which the eggs of insects were capable of enduring without injury; and we subjoin the statement of the latter. "I have ex

posed eggs to a more rigorous trial than the winter of 1709.* Those of several insects, and, among others, the silkworm, moth, and elm-butterfly, were enclosed in a glass vessel, and buried five hours in a mixture of ice

* The year 1709 is celebrated for its rigor, and its fatal effects on plants and animals. Fahrenheit's thermometer fell to one degree below zero, and yet the insects were as numerous in spring as ever.

and sal-gemmæ, (rock salt.) The thermometer fell six degrees below zero. In the middle of the following spring, however, caterpillars came from all the eggs, and at the same time as from those which had suffered no cold. In the following year, I submitted them to an experiment still more hazardous. A mixture of ice and sal gem. with the fuming spirit of nitre, (nitrate of ammonia,) reduced the thermometer twenty-two degrees below zero,

-that is, twenty-one degrees lower than the cold of 1709. They were not injured, as I had evident proof, by their being hatched."

It is, indeed, a singular and unaccountable fact, that the eggs of these insects are incapable of being frozen even by the intense cold now mentioned. Spallanzani discovered this, by crushing some of them with the nail, when he found that their contents remained fluid; and he justly infers, that the included embryos remain equally unfrozen. The final cause of this is easily understood; but the chemical property which resists so severe a trial, has not been ascertained.

The modes by which instinct has taught insects to preserve their eggs during winter, are very various. One of these I have already detailed; but, before leaving the subject, there is another, which, on account of its singularity, I cannot deny myself the pleasure of mentioning; I allude to the cochineal insects, (Coccidæ,) so called from one of the species furnishing the wellknown valuable dye-stuff. These little insects contrive to render their dead bodies useful to their future progeny, by protecting their eggs from the severity of the weather. They die in the act of incubation. Their eggs are deposited under their bodies, which become glued to the spot, and thus serve as a covering. In this state, the

dead insects appear on the bark of trees, like small warts, of various forms. The mother is seldom larger than a peppercorn, yet the number of eggs which she lays amounts to several thousands. Some of them secrete a sort of white silky gum, very like gossamer, as the first bed of their eggs. Some naturalists have supposed this substance to be of the nature of the spider's web; but

the author of 'Insect Transformations' says he has ascertained it to be "precisely similar to the gluten which envelopes the eggs of most insects."

SEVENTH WEEK-WEDNESDAY.

HYBERNATION OF INSECTS.-VARIOUS STATES.

TURNING from the consideration of insect eggs, let us look to some of the other means which the Creator has employed for preserving these minute animals during the rigorous season of the year. Some assume the chrysalis form, in which state they require no food, and can endure a greater degree of cold than in their more perfect condition, though they are much inferior, in this respect, to the eggs already mentioned. We shall take an example of this method of hybernation from the butterfly family, which is remarkable for the variety of modes by which the Author of Nature has provided for the safety of the different species. The history of the large white butterfly, which we select, is not perhaps so peculiar, among the insect tribes, as it is remarkable. It undergoes a double round of transformations in the course of the year, and its instincts are wonderfully adapted to the state of the season in each. From the chrysalis state, these insects assume that of caterpillars, about the last days of April, or the beginning of the following month. They first appear on wing in the middle of May, and, about the end of the same month, lay their eggs in clusters on the under side of cabbage-leaves. In a few days after, the caterpillars come forth, and continue to feed together till the end of June, when they are at their full growth. They then wander about in search of convenient places to fix themselves, where, after their change, the chrysalis may be sheltered. When such are found, they each fasten their tail by a web, and carry a strong thread of the same

round their body, near the head; and, thus firmly secured, hang a few hours, when the chrysalis becomes perfectly formed, and divested of the caterpillar's skin. In fourteen days after this, the fly is on the wing.* Such is the history of their first series of transformations. But a long period of genial weather still remains, and a new succession of changes takes place. The butterfly lays its eggs, which are again converted into caterpillars, and about the end of September, these caterpillars become chrysalides, in which state they are prepared to pass the winter. Now, however, as if acquainted with the change which Nature is about to undergo, they do not seek for protection beneath the fading vegetation which formed their previous retreat, but may be found hanging under the copings of garden walls, under pales, and in other places, where they can have a tolerable shelter from the inclemency of the weather, and yet be in the neighborhood of their food, when they throw off this state of inactivity on the revival of Nature in spring.

An instance of the hybernation of insects, in the caterpillar state, may be found in another branch of this family, that of the marsh fritillary. These small butterflies, the color of which is a brownish orange, variegated with orange and black, are found in the caterpillar state in the month of September. As the season advances, they spin for themselves a fine web, in which they congregate, and under covert of which they pass the winter. During this time, they are so nearly reduced to a torpid state, as to require no food; nor do they venture out of their covering, till invited by the warmth of spring. They have not yet come to their full size, and their growth is suspended during winter. If we pursue their history a little further, we find that, about the end of April, they are in full maturity, and, suspending themselves by the tail, change into chrysalides. "Their mode of suspension,' says Captain Brown, "is a singular instance of the extraordinary power of instinct. They first draw two or three small blades of grass across towards the top, and

* Goldsmith's Animated Nature, Note, val. iv. p. 297,