On the middle part of its body, both above and below, there is a row of seven four-sided pads, which the grub can either expand or contract, making them stick out or lie flat at will. It is by means of these pads that it walks. When it wishes to move forwards it expands the hinder pads, those on the back as well as those on the stomach, and contracts its front pads. The swelling of the hind pads in the narrow gallery fills up the space, and gives the grub something to push against. At the same time the flattening of the front pads, by decreasing the size of the grub, allows it to slip forward and take half a step. Then, to complete the step, the hind-quarters must be brought up the same distance. With this object the front pads fill out and provide support, while those behind shrink and leave room for the grub to draw up its hind-quarters. With the double support of its back and stomach, with alternate swellings and shrinkings, the animal easily advances or retreats along its gallery, a sort of mould which the contents fill without a gap. But if the pads grip only on one side progress becomes impossible. When placed on the smooth wood of my table the animal wriggles slowly; it lengthens and shortens without progressing by a hair’s breadth. Laid on the surface of a piece of split oak, a rough, uneven surface due to the gash made by the wedge, it twists and writhes, moves the front part of its body very slowly from left to right and right to left, lifts it a little, lowers it, and begins again. This is all it can do. The rudimentary legs remain inert and absolutely useless. II THE GRUB’S SENSATIONS Though the Capricorn-grub possesses these useless legs, the germs of future limbs, there is no sign of the eyes with which the fully-developed insect will be richly gifted. The larva has not the least trace of any organs of sight. What would it do with sight, in the murky thickness of a tree-trunk? Hearing is likewise absent. In the untroubled silence of the oak’s inmost heart the sense of hearing would be superfluous. Where sounds are lacking, of what use is the faculty of discerning them? To make the matter certain I carried out some experiments. If split lengthwise the grub’s abode becomes a half-tunnel, in which I can watch the occupant’s doings. When left alone it alternately works for a while, gnawing at its gallery, and rests for awhile, fixed by its pads to the two sides of the tunnel. I took advantage of these moments of rest to inquire into its power of hearing. The banging of hard bodies, the ring of metallic objects, the grating of a file upon a saw, were tried in vain. The animal remained impassive: not a wince, not a movement of the skin, no sign of awakened attention. I succeeded no better when I scratched the wood near it with a hard point, to imitate the sound of some other grub at work in its neighbourhood. The indifference to my noisy tricks could be no greater in a lifeless object. The animal is deaf.