A fourth, _Bolbites onitoides_, compensates us for repetitions which, it is true, widen the scope of the problem but teach us nothing new. She is a handsome Beetle with a metallic costume, green or copper-red according as the light happens to fall. Her four-cornered shape and her long, toothed fore-legs make her resemble our Onites.[14]
[Footnote 14: Cf. _The Sacred Beetle and Others_: chap. xvi.--_Translator's Note_.]
In her, the Dung-beetles' guild reveals itself under a very unexpected aspect. We know insects that knead soft loaves; and here are some which, to keep their bread fresh, discover ceramics and become potters, working clay in which they pack the food of the larvæ. Before my housekeeper, before any of us, they knew how, with the aid of a round jar, to keep the provisions from drying during the summer heats. The work of the Bolbites is an ovoid, hardly differing in shape from that of the Copres; but this is where the ingenuity of the American insect shines forth. The inner mass, the usual dung-cake furnished by the Cow or the Sheep, is covered with a perfectly homogeneous and continuous coating of clay, which makes a piece of solid pottery impervious to evaporation.
The earthen pot is exactly filled by its contents, without the slightest interval along the line of junction. This detail tells us the worker's method. The jar is moulded on the provisions. After the food-pellet has been formed in the ordinary baker's fashion and the egg laid in its hatching-chamber, the Bolbites takes some armfuls of the clay near at hand, applies it to the foodstuff and presses it down. When the work is finished and smoothed to perfection with indefatigable patience, the tiny pot, built up piecemeal, looks as though made with the wheel and rivals our own earthenware in regularity.
The hatching-chamber, in which the egg lies, is, as usual, contrived in the nipple at the end of the pear. How will the germ and the young larva manage to breathe under that clay casing, which intercepts the access of the air?
Have no fears: the pot-maker knows quite well how matters stand. She takes good care not to close the top with the plastic earth which supplied her with the walls. At some distance from the tip of the nipple, the clay ceases to play its part and makes way for fibrous particles, for tiny scraps of undigested fodder, which, arranged one above the other with a certain order, form a sort of thatched roof over the egg. The inward and outward passage of the air is assured through this coarse screen.