But this is not all our professor's peculiarities. One day, as I came to look at my hump-backed pets, I discovered that most of them had shrunk a full third, and had refused to eat and, what surprised me more, refused to wiggle. A closer examination of the box showed that while they had ignored the lilac leaves, they had been gnawing the pasteboard everywhere in the box, even perforating it with a number of holes. The captives in a thin wooden box were similarly affected, and numbers of holes were to be seen. What did it mean? I had been expecting daily to see my full-grown caterpillars either beginning their cocoons or suspending themselves by their tails in readiness for the chrysalis state. Yet they had done neither. Their time had evidently come, but they were not satisfied with their surroundings, and would seem to wish to escape; and yet, having gnawed their way to liberty, deliberately remained in prison! It was some days before I correctly interpreted their curious contradictory actions, and as I remember it now, my hint came from a spider-web which had spread its catch all beneath a lilac-bush, and upon which I discerned a number of tiny balls of sawdust which had chanced to fall upon it. Looking directly above, among the branches, I soon found a wiggler, not only gnawing the wood but with one-third of its body in a burrow in a twig the size of my finger. I had observed him thus for a few moments when he began to back out, drawing with him a tiny ball of sawdust, which he threw out with a slight wiggle, and soon resumed operations. Leaving him to his work, I lost no time in taking the hint, and my box was soon criss-crossed with small twigs, and my remaining wigglers soon found themselves at home and littered my box with their chip pellets. The burrow is first made diagonally to the pith, and then follows the centre for about two-thirds of an inch. I remember having about a half-dozen caterpillars thus at work simultaneously. On the morrow, when I opened the box, all signs of caterpillars and burrows had vanished. Though I looked directly upon the spot where yesterday I had surely seen the open tunnel, no vestige of it now appeared, and its whereabouts could only be guessed by the slight rose-colored stain which the caterpillar had left on the bark below. What had happened?