It is now a long time since I did my utmost to upset the mother’s wise previsions by taking food from the wealthy grubs to increase the store of the poor. In this way I obtained some slight modifications of size, to which the terms giant and dwarf could not, however, be applied; still less did I succeed in changing the sex, whose determination does not in any way depend upon the quantity of food supplied. The Bees and Wasps are not suited to my present purpose. Their grubs are too delicately constituted. What I want is sturdy stomachs capable of enduring severe ordeals. I shall find them in the Dung-beetles, notably in the Sacred Beetle, whose natural portliness will facilitate our appreciation of any change of bulk. The big pill-roller calculates the food of her larvæ precisely: each grub has its loaf, kneaded into the shape of a pear. All these loaves are not strictly equal; some are larger and some smaller, but the difference is only minute. Perhaps these slight inequalities are connected with the sex of the nurslings, as among the Bees and Wasps; the females would receive the larger and the males the smaller rations. I did not take any steps to verify this theory. No matter: the fact remains that the Sacred Beetle’s pear is, in the mother’s opinion, a convenient individual ration. As for me, I can, if I please, alter the size of the loaf, increasing or decreasing it at will. Let us first consider the decrease. In May, I procure four recent pears, containing the egg in the chamber of the terminal nipple. By making an equatorial section, I cut off the hinder half, in the shape of a large spherical cap; the other half, surmounted by its neck, I retain; and I place the four egg-bearing portions in as many small jars, in which there is no danger of either desiccation or excessive damp. With these provisions decreased by half, development takes place as usual; then two of the grubs die, apparently the victims of defective hygiene: my jars are not equal to the burrows, with their pleasant moisture. The two others are still in good condition, ever ready to plug with dung the window which I cut through the wall of the cell when I wish to inspect them. At the end of the active period, I find them remarkably small in comparison with those of their fellows who have been left in possession of the whole pear. The effect of insufficient food is already manifest. What will it be in the perfect insect? In September there emerge from the shells adults such as my hunts in the meadows never yielded, dwarfs, hardly larger than a thumbnail, but correctly shaped in every other respect.