Some days before the moult, split the caterpillar's skin, and you will find the skin which is to take its place already beneath. If, some days before the transformation of the caterpillar into a chrysalis, it is dissected, the rudiments of wings and antennæ may be discovered. If a chrysalis is examined on the outside, all the parts of the future insect can be distinguished under the skin: the wings, the legs, the antennæ, the proboscis, &c.; only, these parts are folded and packed away in such a manner that the chrysalis can make no use of them. It could not, moreover, make use of them on account of their incomplete development. Fig. 127 shows, after Réaumur,[41] a chrysalis magnified and seen from its lower side, on which we observe:--_a_, the wings; _b b_, the antennæ; _t_, the trunk or proboscis. [41] Tome i., p. 382, planche 26, Fig. 6. There is a moment when these parts, pressed one against each other, and as it were swathed up like a mummy, are very easily seen, for they are, as we may say, laid bare. This moment is that in which the pupa has just quitted the caterpillar's skin. It is then still soft and tender. Its body is moistened with a liquid, which, drying rapidly, becomes opaque, coloured, and of a membranous consistency. The result is that the parts which did not cohere in the least when the chrysalis made its first appearance, are fastened together, so that although they could at first be seen, through a layer of transparent fluid, they are now hidden under a sort of veil or cloak. It is necessary to seize then the moment of the birth of the chrysalis, to observe it accurately. On examining the pupa before the liquid which pervades these parts has had time to dry, it resembles the perfect insect. All the exterior parts which belong to the imago can be distinguished. One recognises the head, which is then resting on the thorax; the two eyes and the antennæ (Fig. 128), which are brought forward like two ribbons; the wings also brought over the thorax, but these are separated artificially in the drawing we have given after Réaumur;[42] and lastly in the space left between the wings, the six legs, and the body of the insect. [42] Tome i., p. 382, planche 26, Fig. 7. [Illustration: Fig. 127.--Chrysalis of the large Tortoise-shell Butterfly (_Vanessa polychloros_), magnified, seen from the lower side.] To sum up: the pupa, when it approaches the period for being hatched is only a swaddled butterfly. Directly it has strength enough to rid itself of its wrapping, the insect frees itself from its fetters; it flies away, brilliant and free, and its many-coloured wings glitter in the sun.