The cavity was dug by the Wasps themselves. Of that there is no doubt; for holes so large and so regular do not exist ready-made. The original foundress of the nest may have seized on some cavity made by a Mole, to help her at the beginning; but the greater part of the enormous vault was the work of the Wasps. Yet there is not a scrap of rubbish outside the entrance. Where is the mass of earth that has been removed? It has been spread over such a large surface of ground that it is unnoticed. Thousands and thousands of Wasps work at digging the cellar, and enlarging it as that becomes necessary. They fly up to the outer world, each carrying a particle of earth, which they drop on the ground at some distance from the nest, in all directions. Being scattered in this way the earth leaves no visible trace. The Wasp’s nest is made of a thin, flexible material like brown paper, formed of particles of wood. It is streaked with bands, of which the colour varies according to the wood used. If it were made in a single continuous sheet it would give little protection against the cold. But the Common Wasp, like the ballon-maker, knows that heat may be preserved by means of a cushion of air contained by several wrappers. So she makes her paper-pulp into broad scales, which overlap loosely and are laid on in numerous layers. The whole forms a coarse blanket, thick and spongy in texture and well filled with stagnant air. The temperature under this shelter must be truly tropical in hot weather. The fierce Hornet, chief of the Wasps, builds her nest on the same principle. In the hollow of a willow, or within some empty granary, she makes, out of fragments of wood, a very brittle kind of striped yellow cardboard. Her nest is wrapped round with many layers of this substance, laid on in the form of broad convex scales which are welded to one another. Between them are wide intervals in which air is held motionless. The Wasp, then, often acts in accordance with the laws of physics and geometry. She employs air, a non-conductor of heat, to keep her home warm; she made blankets before man thought of it; she builds the outer walls of the nest in the shape that gives her the largest amount of room in the smallest wrapper; and in the form of her cell, too, she economises space and material. And yet, clever as these wonderful architects are, they amaze us by their stupidity in the face of the smallest difficulty. On the one hand their instincts teach them to behave like men of science; but on the other it is plain that they are entirely without the power of reflection. I have convinced myself of this fact by various experiments.