Before leaving the spot, let us note a fact whose evidence will be of value later. The female was right at the bottom of the burrow; above her, at some distance, was the male: both were struck motionless with fright in the midst of an occupation whose nature we are as yet hardly able to specify. This detail, observed repeatedly in the different burrows dug up, seems to show that each of the two fellow-workers has a definite place.
The mother, more skilled in nursery matters, occupies the lower floor. She alone [[91]]digs, versed as she is in the properties of the perpendicular, which economizes labour while giving the greatest depth. She is the engineer, always in touch with the working-face of the shaft. The other is her labourer. He is stationed in the rear, ready to load the rubbish on his horny hod. Later, the excavatrix becomes a baker: she kneads the cakes for the children into cylinders; the father is then the baker’s boy. He brings her from outside the wherewithal for making flour. As in every well-regulated household, the mother is minister of the interior, the father minister of the exterior. This would explain the invariable position in their cylindrical home. The future will tell us if these conjectures truly correspond with the reality.
For the moment, let us examine at our leisure, in the comfort of our own home, the central clod, so laboriously acquired. It contains a preserved foodstuff in the shape of a sausage nearly as long and as thick as a man’s finger. This is composed of a dark, compact material, arranged in layers, which we recognize as the Sheep-pellets reduced to small crumbs. Sometimes the dough is fine and almost homogeneous from one end of [[92]]the cylinder to the other; more often the piece is a sort of hardbake, in which large fragments are held together by an amalgamation of cement. The baker apparently varies the more or less careful composition of her confectionery according to the time at her disposal.
The stuff is tightly packed into the closed end of the burrow, where the walls are smoother and more elaborately treated than in the rest of the shaft. The point of the knife easily rids it of the surrounding earth, which peels off like a rind. In this way I obtain the food-cylinder free from any earthy stain.
When this is done, let us enquire into the matter of the egg, for this pastry has certainly been manipulated for the sake of a grub. Guided by what I learnt in the old days from the Geotrupes, who lodge the egg at the lower end of their black-pudding, in a special recess contrived in the very heart of the provisions, I look to find the egg of the Minotaur, their near kinsmen, in a hatching-chamber right at the bottom of the sausage. I am mistaken. The egg sought for is not at the spot anticipated, nor at the [[93]]other end, nor in any part whatsoever of the victuals.
A search outside the provisions reveals it me at last. It is below the food, in the sand itself, and has benefited by none of the meticulous cares wherein mothers excel. There is here not a smooth-walled chamber, such as the delicate skin of the new-born larva would seem to demand, but a rough, irregular cavity, the result of a mere falling in rather than of material ingenuity. The grub is to be hatched in this rude crib, at some distance from its provisions. To reach the food, it will have to demolish and pass through a ceiling of sand some millimetres thick. As regards her offspring, the Minotaur mother is an expert in the art of sausage-making, but she knows nothing at all of the endearments of the cradle.
Anxious to watch the hatching and observe the growth of the larva, I install my find in cells reproducing as nearly as may be the natural conditions. A glass tube closed at one end of the same diameter as the burrow receives first a bed of moist sand to represent the original soil. On the surface of this layer I place the egg. A little of the same sand forms the ceiling through which [[94]]the new-born grub must pass to reach the provisions. There are none other than the regulation sausage, rid of its earthy rind. A few careful strokes of the rammer make it occupy the available space. Lastly, a plug of wet, but not dripping cotton-wool fills up the cell completely. This will be a source of permanent moisture, similar to that of the depths in which the mother establishes her family. The provisions will thus remain soft, in accordance with the youthful consumer’s needs.
This softness of the food and the flavour produced by the fermentation due to moisture probably have something to say to the instinct to bore deeply at the time of egg-laying. What do the father and mother really want? Do they dig to ensure their own welfare? Do they go so low down in order to find an agreeable temperature and moisture when the fierce summer heat prevails? Not at all. Endowed with a robust constitution and loving the sun’s kisses as other insects do, they both inhabit, until the family is founded, a modest dwelling in a convenient position. Not even the inclemencies of winter drive them to seek a better shelter. [[95]]
At nesting-time it is another matter. They descend to a great depth underground. Why? Because their family, which is hatched about June, must find soft food awaiting it at a time when the heat of summer will bake the soil hard as a brick. The tiny sausage, if it lay at a depth of ten or twenty inches, would become hard as horn and uneatable; and the grub, incapable of biting into the tough ration, would perish. It is important therefore that the victuals should be cellared at a depth where the most violent heat of the sun cannot lead to desiccation.
Many other food-packers know the risks of excessive dryness. Each has his own method of warding off the danger. The Geotrupes makes his home under the voluminous heap dropped by the Mule, an excellent obstacle to speedy desiccation. Besides, he works in autumn, the season of frequent showers; moreover, he gives his product the shape of a big roly-poly, of which the middle part, the only part used, gives up its moisture very slowly. For these several reasons, he digs burrows of medium depth.