Fig. 12.—Section of the Stercoraceous Geotrupe’s sausage at its lower end, showing the egg and the hatching-chamber.
The burrow dug by the Geotrupe for the benefit of her grub is hardly deeper than that of the Copris or the Sacred Beetle, notwithstanding the difference of the seasons. Three decimetres,[3] roughly speaking: that is all that I find in the fields, where nothing occurs to limit the depth.
The contents of the rustic dwelling take the form of a sort of sausage or pudding, which fills the lower part of the cylinder and fits it exactly. Its length is not far short of a couple of decimetres[4]. This sausage is almost always irregular in shape, now curved, now more or less dented. These imperfections of the surface are due to the accidents of a stony ground, which the insect does not always excavate according to the canons of its art, which favours the straight line and the perpendicular. The moulded material faithfully reproduces all the irregularities of its [[123]]mould. The lower extremity is rounded off like the bottom of the burrow itself; at the lower end of the sausage is the hatching-chamber, a round cavity which could hold a fair-sized hazel-nut. The respiratory needs of the germ demand that the side-walls should be thin enough to allow easy access to the air. Inside, I catch the gleam of a greenish, semi-fluid plaster, a dainty which the mother has disgorged to form the first mouthfuls of the budding worm.
In this round hole lies the egg, without adhering in any way to the surrounding walls. It is a white, elongated ellipsoid and is of remarkable bulk in proportion to the insect. In the case of Geotrupes Stercorarius, it measures seven to eight millimetres in length by four in its greatest width.[5] The egg of Geotrupes Hypocrita is a little smaller. [[125]]
[1] About 61 cubic inches.—Translator’s Note. [↑]
[2] Over 39 inches.—Translator’s Note. [↑]
[3] 11 to 12 inches.—Translator’s Note. [↑]