We must hasten to abandon this silly notion: the tunnel is infinitely narrow and blocked with shavings, so that any such descent would be impossible. Besides, according to the direction of the stalk, which may be either downwards or upwards, a fall in one acorn would mean an ascent in another.
A second, no less risky explanation suggests itself. You say to yourself:
‘The Cuckoo lays her egg in the grass, anywhere; she picks it up in her beak and goes and places it as it is in the Warbler’s narrow nest.’
Can the Weevil adopt a similar method? Can [[91]]she use her rostrum to push her egg to the base of the acorn? I cannot see that the insect has any other implement capable of reaching this remote hiding-place.
And yet we must hastily reject this quaint explanation as a despairing resource. Never does the Weevil lay her egg in the open and then take it in her beak. If she did, the delicate germ would infallibly perish, destroyed in the attempt to push it down a narrow, half-choked passage.
My perplexity is great; and it will be shared by any of my readers who are acquainted with the Weevil’s structure. The Grasshopper owns a sabre, a laying-tool which sinks into the ground and sows the eggs at the requisite depth;[2] the Leucospis is endowed with a probe which makes its way through the Chalicodoma’s[3] masonry and slips the egg into the cocoon of the fat, sleepy larva; but this Weevil of ours has none of these rapiers, daggers or larding-pins; she has nothing at the tip of her abdomen, absolutely nothing. And yet she has but to apply that tip to the narrow opening of the well for the egg to be lodged, forthwith, at the very bottom.
Anatomy will supply the key to the riddle, which is otherwise undecipherable. I open the mother’s abdomen. What meets my eyes astounds [[92]]me. There is here, occupying the whole length of the body, an extraordinary piece of mechanism, a stiff, red, horny rod, I was almost saying a rostrum, so closely does it resemble that of the head. It is a tube, slender as a horse-hair, widening slightly like a blunderbuss at the free end and swollen like an egg-shaped capsule at the base.
This is the laying-tool, equalling the bradawl in length. As far as the perforating beak reaches, so far can the egg-probe reach, that inner beak. When working upon her acorn, the Weevil chooses the point of attack so that the two complementary instruments can both reach the desired point, the base of the fruit.
The rest now stands self-explained. When the work of drilling is finished and the gallery ready, the mother turns round and places the tip of her abdomen over the entrance. She unsheathes and protrudes her internal mechanism, which readily sinks through the loose shavings. No sign appears of the directing probe, so quickly and discreetly does it work; no sign appears either when, after the egg has been placed in position, the instrument goes up again and gradually slips back into the abdomen. It is over; the mother departs and we have seen none of her little secrets.
Was I not right to persist? An apparently insignificant fact has told me definitely what the Larini had already led me to suspect. The long-beaked [[93]]Weevils have an inner probe, an abdominal rostrum, which no outward sign betrays; they possess, hidden away in their belly, the counterpart of the Grasshopper’s sabre and of the Ichneumon-fly’s larding-pin. [[94]]