brought down the thermometer to 22° below zero—a deadly chill—and yet they survived with apparent

impunity, and afterwards lived to hatch duly. Then as to their heat-resisting powers, some tropical insects habitually lay their eggs in sandy, sun-scorched places, where the hand cannot endure to remain a few moments; the heat rising daily to somewhere about 190° of the thermometer—and we know what a roasting one gets at 90° or so. Yet they thrive through all this.

For a short time previous to hatching, the form and colour of the caterpillar is faintly discoverable through the semi-transparent egg-shell. The juvenile Caterpillar, or Larva, gnaws his way through the shell into the world, and makes his appearance in the shape of a slender worm, exceedingly minute of course, and bearing few of the distinctive marks of his species, either as to shape or colouring. On finding himself at liberty, in the midst of plentiful good cheer, he at once falls vigorously to work at the great business of his life—eating; often making his first meal—oddly enough—off the egg-shell, lately his cradle. This singular relish, or digestive pill, swallowed, he addresses himself to the food that is to form the staple fare during the whole of his caterpillar existence—viz. the leaves of his food-plant, which at the same time is his home-plant too.

At this stage his growth is marvellously rapid, and few creatures can equal him in the capacity for doubling his weight—not even the starved lodging-house "slavey," when she gets to her new place, with carte blanche allowance and the key of the pantry; for, in the course

of twenty-four hours, he will have consumed more than twice his own weight of food: and with such persevering avidity does he ply his pleasant task, that, as it is stated, a caterpillar in the course of one month has increased nearly ten thousand times his original weight on leaving the egg; and, to furnish this increase of substance, has consumed the prodigious quantity of forty thousand times his weight of food—truly, a ruinous rate of living, only that green leaves are so cheap.

But the life of a caterpillar, after all, is not merely the smooth continual feast he would doubtless prefer it to be; it is interrupted, several times in its course, by the necessity nature has imposed upon him of now and then changing his coat—to him a very troublesome, if not a painful affair.

For some time previous to this phenomenon, even eating is nearly or quite suspended,—the caterpillar becomes sluggish and shy, creeping away into some more secluded spot, and there remaining till his time of trouble is over. Various twitchings and contortions of the body now testify to the mal-aise of the creature in his old coat, which, though formed of a material capable of a moderate amount of stretching, soon becomes outgrown, and most uncomfortably tight-fitting, with such a quick-growing person inside it: so off it must come, but it being unprovided with buttons, there's the rub. However, with a great deal of fidgeting and shoulder-shrugging, he manages to tear his coat down the back, and lastly, by patient efforts, shuffles off the old rag;

when, lo! underneath is a lustrous new garment, somewhat similar, but not exactly a copy of the last, for our beau has his peculiar dress for each epoch of his life,—the most splendid being often reserved for the last.

This change of dress ("moulting," it is sometimes called) is repeated thrice at least in the creature's life, but more generally five or six times. Not only does the outer husk come off at these times, but, wonderful to relate! the lining membrane of all the digestive passages, and of the larger breathing tubes, is cast off and renewed also.

After each moult, the caterpillar makes up for his loss of time by eating more voraciously even than before, in many instances breaking his fast by making a meal of his "old clo'"—an odd taste, first evinced, as we have seen, in earliest infancy, when he swallowed his cradle.

On Plate I. are shown the chief varieties of form taken by the caterpillars of our British butterflies, and a glance at these will give, better than verbal descriptions, a general idea of their characteristics.

Their most usual shape is elongated and almost cylindrical, or slightly tapering at one or both ends. Of these, some are smooth, or only studded with short down or hairs; such are the caterpillars of the Swallow-tail butterfly (fig. 1), of the Brimstone (fig. 2), Clouded Yellows, and Garden, and other white butterflies. Others, of the same general form, are beset with long branched spines, making perfect chevaux-de-frise; such

are those of the Peacock, Red Admiral, Painted Lady, and the Silvery Fritillaries.

The caterpillars of another large section have the body considerably thicker in the middle (rolling-pin shaped), and the tail part two-forked, or bifurcate. This form belongs to the numerous family that includes the Meadow-brown (fig. 3), the Ringlets, and many others.

The bizarre personage, at fig. 4, turns to the graceful White Admiral butterfly.

The Purple Emperor begins his royal career in the curious form shown at fig. 5—a shape unique among British butterflies, as beseems that of their sovereign; and he carries a coronet on his brow already.

All those beautiful little butterflies called the Hair-streaks (fig. 9), the Blues (fig. 10), and the Coppers, have very short and fat caterpillars, that remind one forcibly of wood-lice—a shape shared also by that small butterfly with a big name, the Duke of Burgundy Fritillary (fig. 8), an insect very distinct from the Fritillaries above mentioned with thorny caterpillars.

The legs of a caterpillar are usually sixteen in number, and composed of two distinct kinds, viz. of six true legs, answering to those of the perfect insect, and placed on the foremost segments of the body; and of ten others, called "prolegs;" temporary legs, used principally for strengthening the creature's hold upon leaf or branch.

Like the rest of its body, the caterpillar's head widely

differs in structure from that of the perfect insect, being furnished with a pair of jaws, horny and strong, befitting the heavy work they have to get through, and shaped like pincers, opening and shutting from side to side, instead of working up and down after the manner of the jaws in vertebrate animals. This arrangement offers great convenience to the creature, feeding, as it is wont to do, on the thin edge of a leaf. It is a curious sight to watch a caterpillar thus engaged. Adhering by his close-clinging prolegs, and guiding the edge of the leaf between his forelegs, he stretches out his head as far as he can reach, and commences a series of rapid bites, at each nibble bringing the head nearer the legs, till they almost meet; then stretching out again the same regular set of mouthfuls is abstracted, and so on, repeating the process till a large semi-circular indentation is formed, reaching perhaps to the midrib of the leaf; then shifting his position to a new vantage ground, the marauder recommences operations, another sweep is taken out, then another, and soon the leaf is left a mere skeleton.

But a change, far more important than mere skin-shifting, follows close upon the animal's caterpillar-maturity, complete as soon as it ceases to grow.

The form and habits of a worm are to be exchanged for the glories and pleasures of winged