The provisions, therefore, even though they have to last but three or four weeks, are exposed to the risk of drying up before that time and becoming uneatable. When, instead of the tender bread of the start, the unhappy worm finds no food for its teeth but a repulsive crust, hard as a pebble and unassailable, it is bound to perish of hunger. And it does, in fact, so perish. I have found numbers of these victims of the August sun who, after eating plentifully of the fresh victuals and digging themselves a cell, had succumbed, unable to continue biting into fare too hard for their teeth. There remained a thick shell, a sort of closed oven, in which the poor wight lay baked and shrivelled up. While the worm dies of hunger in the shell turned to stone by desiccation, the full-grown insect that has finished its transformations dies there too, for it is incapable of bursting the enclosure and freeing itself. I shall return later to the final delivery and will linger no more on this point. Let us occupy ourselves solely with the woes of the worm. The drying-up of the victuals is, we say, fatal to it. This is proved by the grubs found baked in their oven; it is also proved, in a more precise fashion, by the following experiment. In July, the period of active nidification, I place in wooden or cardboard boxes a dozen pears dug up, that morning, from the native spot. These boxes, carefully closed, are put away in the dark, in my study, where the same temperature reigns as outside. Well, in none of them is the infant reared: sometimes the egg shrivels; sometimes the worm is hatched, but very soon dies. On the other hand, in tin boxes or glass receptacles, things go very well: not one attempt at rearing fails. Whence do these differences arise? Simply from this: in the high temperature of July, evaporation proceeds apace under the pervious wooden or cardboard screen; the alimentary pear dries up and the poor worm dies of hunger. In the impermeable tin boxes, in the carefully-sealed glass receptacles, evaporation does not take place, the provisions retain their softness and the grubs thrive as well as in their native burrow.