One knows the gentle manoeuvres by which nature conducts the young of the higher animals from the embryonic existence to the independent life, adapting the old organs to new functions. Here, this is not done. It is not a simple change of condition. The destination is not merely different, but contrary, with a violent contrast. Therefore, instruments fitted for an entirely novel existence are required, and the abolition and definitive sacrifice of the primitive organism. The revolution, which for all other beings is so well concealed, is here entirely thrown open. And we are enabled to scrutinize with our eyes this astonishing _tour de force_ in numerous grubs which undergo the great change in the light of day, suspended to the branch of a tree by a silken cable. The effort is worthy of our admiration and pity. To see yonder nymph, short and feeble, soft and gelatinous, without arms or paws, contriving, by the skill with which it expands and contracts its rings, to escape from the heavy and rough machine which it was at first, flinging aside its limbs, setting free its head, and--one hardly dares to record the fact--throwing off its body, and rejecting many of its principal internal organs! [Illustration] This little body, when it has thus escaped from its long heavy mask (living, nevertheless, but a moment since, a life full of energy), will dangle, and grow dry, and skilfully ascend to its silken fastening. There it prepares to fix itself in its new "Me" as a nymph, while its former "Me," tossed about by the wind, is speedily driven I know not whither. All is, and ought to be, changed. _The legs will not again be the legs._ It will need lighter organs. What can the child of the air, which can balance on the point of a blade of grass, do with those coarse short feet, armed with hooks, vent-holes, and so many heavy implements? _The head will not be the head_; at least, the enormous apparatus of mandibles will disappear, and also that of the muscles by which they were energetically moved. All is thrown aside with the mask. A colossal change! From a masticator the animal becomes a sucker. A flexible proboscis emerges. If anything in the grub appeared of a fundamental character, it was the digestive apparatus. Ah, well! this basis of its being is no more. The absorbing throat--the powerful stomach--the greedy entrails,--all are suppressed, or reduced nearly to nothing. What would they avail the new being which, in certain species of butterflies, dispenses with sustenance, has no mouth but by agreement, and is so completely freed from digestion that frequently it has not even an inferior orifice? It abandons without difficulty its thenceforth useless furniture, and expectorates the skin of its stomach!