Let us now go back to the most curious part of the furnishing, the cover or inner door of the entrance. It is like an oval skull-cap, white and hard as chalk, smooth within and rough without, with some resemblance to an acorn-cup. The rough knots show that the material is supplied in small, pasty mouthfuls, which become solid outside in little lumps. The animal does not remove them, because it is unable to get at them; but the inside surface is polished, being within the grub’s reach. This singular lid is as hard and brittle as a flake of limestone. It is, as a matter of fact, composed solely of carbonate of lime, and a sort of cement which gives consistency to the chalky paste. I am convinced that this stony deposit comes from a particular part of the grub’s stomach, called the chylific ventricle. The chalk is kept separate from the food, and is held in reserve until the right time comes to discharge it. This freestone factory causes me no astonishment. It serves for various chemical works in different grubs when undergoing transformation. Certain Oil-beetles keep refuse in it, and several kinds of Wasps use it to manufacture the shellac with which they varnish the silk of their cocoons. When the exit way is prepared, and the cell upholstered in velvet and closed with a threefold barricade, the industrious grub has finished its task. It lays aside its tools, sheds its skin, and becomes a pupa—weakness personified, in the swaddling-clothes of a cocoon. The head is always turned towards the door. This is a trifling detail in appearance; but in reality it is everything. To lie this way or that in the long cell is a matter of great indifference to the grub, which is very supple, turning easily in its narrow lodging and adopting whatever position it pleases. The coming Capricorn will not enjoy the same privileges. Stiffly encased in his horny armour, he will not be able to turn from end to end; he will not even be capable of bending, if some sudden curve should make the passage difficult. He must, without fail, find the door in front of him, or he will perish in the transformation-room. If the grub should forget this little matter, and lie down to sleep with its head at the back of the cell, the Capricorn would be infallibly lost. His cradle would become a hopeless dungeon. But there is no fear of this danger. The “bit of intestine” knows too much about the future to neglect the formality of keeping its head at the door. At the end of spring the Capricorn, now in possession of his full strength, dreams of the joys of the sun, of the festivals of light. He wants to get out.