CHAPTER V
MINOTAURUS TYPHŒUS: FIRST ATTEMPTS AT OBSERVATION
Long ago, the Minotaur’s cousins, the Geotrupes, afforded me a delightfully unusual spectacle, that of a prolonged association in pairs, a real domestic couple, working in common for the children’s welfare. Philemon and Baucis, as I used to call them, prepared their board and lodging with equal ardour. Philemon, the sturdier of the two, compressed the food by pushing it with his fore-arms; Baucis explored the heap on the surface, picking out the best part and lowering by the armful the wherewithal to manufacture the enormous sausage. It was magnificent to see the mother sifting and the father compressing.
A cloud overshadowed this exquisite picture. My subjects occupied a cage wherein any inspection demanded an excavation on my part, discreetly conducted, it is true, but enough to startle the labourers and make [[99]]them stop work. With unsparing patience, I thus obtained a series of snapshots which the logic of things, that delicate cinematographer, afterwards combined to form a living scene. I wished for more than this: I should have liked to observe the couple in continuous action, from the beginning to the end of their task. I had to abandon the idea, so impossible did it seem to me to observe the mysterious underground happenings without perturbing excavations.
To-day, my ambition to achieve the impossible has returned. The Minotaur proclaims himself a rival of the Geotrupes; he even appears to be their superior. I propose to follow his actions underground, at a depth of a yard and more, completely at my ease, without in any way distracting the insect from its occupations. To do this I shall need the eyes of a Lynx, which are said to be capable of piercing the opaquest night, whereas I have only my ingenuity to fall back upon in endeavouring to see plainly in the dark. Let us see what it can do.
To begin with, the direction of the burrow enables me to foresee that my plan is not altogether absurd. When digging her nest, the Minotaur descends perpendicularly. If [[100]]she worked at random, following all sorts of directions, excavation would demand an infinite area of soil, out of all proportion to the means at my disposal. Well, her invariable adherence to the perpendicular informs me that I need not trouble about the quantity of sand available, but only about the depth of the bed. In these conditions, the undertaking is not unreasonable.
As good luck will have it, I possess a glass tube which has long been diverted from chemistry and placed at the service of entomology. It is a yard or more in length, and over an inch in width. If fixed in a vertical position, it will do, I think, for the Minotaur’s shaft. I close one end with a plug and fill the tube with a mixture of fine sand and moist clay soil, packing the mixture in layers with a ramrod. This column will be the plot of ground allotted to the digger to work in.
But it must be kept upright and completed with different accessories essential to successful operation. For this purpose, three bamboo canes are planted in the earth contained in a large flower-pot. Joined at their tips, they form a tripod, a frame supporting the whole structure. The tube is set up in the [[101]]centre of the triangular base. A small earthenware pie-dish with a hole made in the bottom, receives the open upper end, which projects a little and holds a layer of earth that comes level with the brim. This will represent, around the mouth of the shaft, the space in which the insect can attend to its business, either to shoot the rubbish from the shaft or to gather the provisions round about. Lastly, a glass bell, fitting into the dish, prevents escape and preserves the slight quantity of moisture needed. A few supporting strings and bits of wire keep the whole thing firmly fixed.
We must not overlook one most important detail. The diameter of the tube is about twice that of the natural burrow. Therefore, if the insect digs along the axis and in an exactly perpendicular direction, it will have at its disposal more than the required width. It will obtain a channel lined on every side by a wall of sand a few millimetres thick. We may however assume that the digger, knowing nothing of geometrical precision and ignorant of the conditions provided for it, will take no account of the axis and will deviate from it to one side or the other. Moreover, the least additional [[102]]resistance in the substance traversed will cause the Beetle to turn aside slightly, now hither, now thither. Consequently the glass wall will be completely denuded at sundry points; windows will be formed, chinks upon which I rely to make observation possible, but which will be hateful to the darkness-loving workers.