The Wasps’ work went on as if it had never been interrupted. The worker-Wasps attended to the grubs and the building at the same time. They began to raise a wall round the most thickly populated combs; and it seemed as though they might intend to build a new envelope, to replace the one ruined by my spade. But they were not repairing; they were simply carrying on the work from the point at which I interrupted it. Over about a third of the comb they made an arched roof of paper scales, which would have been joined to the envelope of the nest if it had been intact. The tent they made sheltered only a small part of the disk of cells. As for the wood I provided for them, they did not touch it. To this raw material, which would have been troublesome to work, they preferred the old cells that were no longer in use. In these the fibres were already prepared; and, with a little saliva and a little grinding in their mandibles, they turned them into pulp of the highest quality. The uninhabited cells were nibbled into pieces, and out of the ruins a sort of canopy was built. New cells could be made in the same way if necessary. Even more interesting than this roofing-work is the feeding of the grubs. One could never weary of the sight of the rough fighters turned into tender nurses. The barracks become a crêche. With what care those grubs are reared! If we watch one of the busy Wasps we shall see her, with her crop swollen with honey, halt in front of a cell. With a thoughtful air she bends her head into the opening, and touches the grub with the tip of her antenna. The grub wakes and gapes at her, like a fledgling when the mother-bird returns to the nest with food. For a moment the awakened larva swings its head to and fro: it is blind, and is trying to feel the food brought to it. The two mouths meet; a drop of syrup passes from the nurse’s mouth to the nurseling’s. That is enough for the moment: now for the next Wasp-baby. The nurse moves on, to continue her duties elsewhere. Meanwhile the grub is licking the base of its own neck. For, while it is being fed, there appears a temporary swelling on its chest, which acts as a bib, and catches whatever trickles down from the mouth. After swallowing the chief part of the meal the grub gathers up the crumbs that have fallen on its bib. Then the swelling disappears; and the grub, withdrawing a little way into its cell, resumes its sweet slumbers. When fed in my cage the Wasp-grubs have their heads up, and what falls from their mouths collects naturally on their bibs. When fed in the nest they have their heads down. But I have no doubt that even in this position the bib serves its purpose.