But here length of time is not enough: the boring-tool is absolutely unmanageable inside the nut-shell. It is so long that, to implant it at the point to be drilled, the Weevil, when she works outside, is obliged to stand erect. For lack of space under the low ceiling of the shell, this position and the alternate tacking about become impossible.
However patient she herself may be and however well-armed we suppose the tip of her drill to be, the Weevil, prevented from employing her auger by the narrowness of the premises, would perish in her coffer. She would die a victim to her inordinate machinery, which serves excellently well for pushing the egg into place, but which would be [[109]]very unwieldy if the prisoner had to effect her own delivery.
Given a less exaggerated rostrum, just a short and powerful punch, the Weevil, methinks, would not abandon the nut while she was still in the larva stage, the danger of the Field-mouse notwithstanding. It is a delightful laboratory for the remodelling-process of the metamorphosis. The shell, it is true, lies on the surface of the soil, unsheltered and exposed to the north-wind. But what does the cold matter, provided that we keep dry? The insect has little to fear from the frosts. Its slumbers are all the sweeter when the torpor attending the renewal of its being is increased by the torpor due to a low temperature.
I am persuaded of it: if she carried a less cumbersome drill, the Balaninus would not change her quarters the moment the kernel of her hazel-nut was consumed. My conviction is based on the habits of other Weevils, in particular Gymnetron thapsicola, Germ., who exploits the capsules of a mullein, Verbascum thapsus, Lin., the shepherd’s club, a frequent denizen of the tilled fields. As cells these capsules are, though less in volume, almost the equivalent of the hazel-nut.
They consist of strong shells, formed of two pieces closely joined, with no communication whatever with the outside world. A Weevil of humble size and modest attire takes possession of them in May and June as lodgings for her larvæ, which [[110]]gnaw the placenta of the fruit, laden with unripe seeds.
In August the plant is withered, scorched by the sun, but still standing and topped with its compact spike of capsules. Open some of these shells, almost as solid as cherry-stones. Inside is the Weevil in the adult state. Open them in winter: the Gymnetron has not gone. Open them for the last time in April: the little Weevil is still at home.
Meanwhile, fresh mulleins have sprouted hard by; they flower; their shells attain the right degree of ripeness: the time has come to leave, to go and establish one’s family. Not till then does the solitary demolish her hermitage, her capsule, which has protected her so faithfully hitherto.
And how does she do so? It is quite simple. Her rostrum is a short bradawl, easily wielded therefore, even in the confined space of a cell. The shell, moreover, is not too strong. It is a very dry vellum wrapper rather than a hard wooden wall. The recluse drives her short-handled pick into it; she stabs and thumps and brings the wall crumbling down. And now hurrah for the joys of the sun! Hurrah for the yellow flowers, with stamens all bristling with violet hairs!
Considering their tools, in one case of exaggerated length under a too low ceiling, in another short and suited to the space available in the cell, are not both these insects happily inspired, the first [[111]]in leaving her nut prematurely, while the grub’s powerful shears enable her to do so, the second in spending three parts of the year in the security of her shell, quitting it only at the time of the wedding on the friendly plant? Thus do we see the impeccable logic of the instincts revealed, even in the humblest creatures. [[112]]