After installing her observatory, Claire proceeds to lie in wait, hiding behind some branches beside the poplar, whose foliage is in full view. She watches in the morning; she watches when the heat of the day has come; she watches in the afternoon. Next day, she begins again; on the day after that, she is still at it; and so she continues until at last fortune smiles upon her. O blessed patience, of what are you not capable! The swarm of Odyneri, out in search of larvæ, were, on their return, warned by the smell of nitrobenzene of the presence of the transplanted and game-laden poplar. Why make distant expeditions when the quarry abounds outside one’s door? The little tree was extensively exploited. Under such conditions the huntress was not long in revealing the secret of her tactics. Over and over again Claire witnessed the act of murder by the dagger. But she paid dearly for satisfying [[208]]our common curiosity; she had to keep her room for several days as a result of sunstroke. For that matter, she was prepared for the misadventure, well knowing, from my own example, that this is the assured reward of observations made beneath an implacable sun. May the eulogies of science repay her for a little headache! The results of her watches agreed at all points with those of my own. I shall explain them by telling what I saw myself.
Now for my turn. When the bundle of reeds selected by the Odyneri reached me, I was occupied with a most interesting question, as will be proved by the details reserved for another chapter.[4] I was endeavouring to make the various Hunting Wasps, the species of whose prey was known to me, operate under a wire cover in my insect laboratory. This would determine the precise spots into which the sting was driven. My captives, confronted with their ordinary game, for the most part refused to unsheathe their weapons; others, less intent upon outdoor hunting, accepted the offer and stabbed their victims under my magnifying-glass. Why should not the Nest-building Odynerus be among these bold ones? [[209]]
We will try. I have plenty of Chrysomela-grubs, received from Orange; I keep them under a wire-gauze dome, with an eye to their metamorphoses and their perfume-stills. The game is at hand; the huntress is lacking. Where shall I catch her? I have only to ask Claire, who will hasten to send her. This is a sure expedient, but I hesitate to employ it: I fear lest the insect should reach me demoralized by the jolting of the cart and the tedium of a long captivity. To this bored and wearied creature an encounter with the Chrysomela will almost surely be a matter of indifference. I must have something better: I want the insect captured that moment with its aptitudes in their prime.
In front of my door is a field of yellow fennel-flower, an ingredient of that ill-famed liquor, absinthe. From its umbels Wasps, Bees and Flies of all sorts drink their fill. Let us take the net and see. The banqueters are numerous. I inspect the rows of plants amid the drinking-songs, the buzzing and the shrilling of the insects. Praise the Lord, here is the Odynerus! I catch one, I catch two, I catch six of them and I hurry back to my workroom. Fate is favouring me beyond my desires: my [[210]]six captures belong to the Nest-building Odynerus and all the six are females. Any one passionately interested in a problem and suddenly discovering the data required for its solution will understand my emotion. The joy of the moment has its anxious side: who knows what turn things will take between the huntress and the quarry? I shift an Odynerus and a Chrysomela-larva into a bell-glass. To stimulate the assassin’s ardour, I set the glass cage in the sun. Here is the story of the drama, told in detail.
For a good quarter of an hour, the captive clambers up the sides of the bell-glass, crawls down again and up again, seeking an outlet whereby to escape, and seems to pay no attention to the game. I was already despairing of success when suddenly the huntress falls upon the larva, turns it over, belly upwards, clasps it and stings it thrice in succession in the thorax, particularly under the neck, in the median region, a point at which the sting is more insistent than elsewhere. The close-clasped larva does its utmost to protest, emptying its scent-bottles and oiling itself with petrol; but these defensive tactics have no effect. Indifferent to the heady perfume, the Odynerus performs [[211]]her operation, wielding her lancet with the same certainty as if the patient were scentless. Thrice the sting is driven in, to kill the motor nerves in the three ganglia of the thorax. I repeat the experiment with other subjects. Few refuse to attack the prey; and each time three stings are administered with marked insistence at the point under the neck. What I saw under artificial conditions Claire, on her side, saw under conditions of liberty, in the open air, on the leaves of the transplanted poplar. The two collaborators, she and I, arrived at precisely the same result.
The operation is rapidly performed. Then the Odynerus, while dragging her prey along, belly to belly, munches at its neck for a considerable time, but without causing any wound. This action may well be equivalent to the practice of the Languedocian Sphex and the Hairy Ammophila,[5] when, without inflicting a bruise, the one nibbles at the neck of her Ephippiger and the other at that of her Grey Worm, in order to compress and paralyse the cervical ganglia. I of course take possession of the torpid larvæ. The victim is absolutely inert, [[212]]save for a slight quivering of the legs, which soon ceases. When laid upon its back, the larva no longer stirs. It is not dead, however; that I have been able to prove. Its dull vitality is affirmed in another manner. During the first few days of this lethargy which knows no awakening, droppings are ejected until the intestine is empty.
On renewing my experiments, I witness something so singular that I am at first baffled. This time the prey is seized by the anal extremity and the sting is driven several times into the last segments, underneath the abdomen. This is the usual operation reversed and performed upon the hinder segments, instead of those of the thorax. The surgeon and the patient, who are head to head in the normal method, are in the present instance head to tail. Can it be by inadvertence that the operator is confusing the two ends of the grub and stinging the tip of the abdomen under the impression that she is stinging the neck? I believe it for a moment, but am soon undeceived. Instinct does not make mistakes of this sort.
For now, having finished thrusting with her sting, the Odynerus clasps the creature [[213]]and begins slowly, with great bites of the mandibles, to munch the last three segments, on the dorsal surface. A manifest gluttony accompanies these bites; all the mouth-parts are brought into play, as though the insect were feasting on some exquisite dish. Meanwhile the grub, bitten to the quick, desperately works its short legs, whose activity is not at all diminished by the stings administered behind; it struggles violently, protesting with its head and mandibles. The other takes no notice and continues gnawing at the larva’s rump. This lasts for ten or fifteen minutes; then the bandit releases the sufferer and leaves it where it lies, without troubling about it any further, instead of carrying it with her as she would not fail to carry game intended for the nest. Soon afterwards, the Odynerus begins to lick her fingers, as though she had been consuming some toothsome dainty: time after time she passes her tarsi between her mandibles; she is washing her hands after rising from table. What has she been eating? I must once more watch the epicure squeeze the juice from the rump.
Ever obliging, provided that I practise a little patience, my six captives, one after the other, operate on the Chrysomela-larvæ, at [[214]]one time in front, as game for the family, at another behind, as a little addition to their own diet. The honey with which I serve them on spikes of lavender does not make them forget this horrible treat. The tactics employed in obtaining it, though the same in the general aspect, vary in detail. The larva is always seized by the hinder end and the stings are administered in succession from back to front, on the ventral surface. Sometimes the abdomen only is attacked, sometimes the thorax also, when the victim is deprived of all movement. Evidently the object of these stings is not the immobility of the larva, since the latter can move quite well, ambling along, wounded though it be, when the sting has not gone higher than the abdomen. Inertia is indispensable only in the case of victuals intended for the cells. If the Odynerus is working on her own behalf and not for her family, it matters little to her whether the grubs whose dainties she covets struggle or not; it is enough if all resistance in the part to be exploited is abolished by paralysis. This paralysis, moreover, is quite accessory; and each huntress neglects or practises it at will, bearing more or less forward, without any fixed rule. When the sated Odynerus releases [[215]]the grub whose rump she has been chewing, it is sometimes therefore inert, like those intended for the cells, and sometimes endowed with almost as much activity as the untouched grubs, from which it differs only by the absence of its anal pimple, its support which reminds us of a cripple sitting in a bowl.
I examine the helpless ones. The anal blister has disappeared, nor can I make it reappear by squeezing the tip of the abdomen with my fingers. For the rest, in the place of this blister my pocket-lens shows me torn, rugged tissues; the end of the intestine is in tatters. Every elsewhere all around are bruises and contusions, but no gaping wounds. It is with the contents of the blister then that the Odynerus so deliciously slakes her thirst. When she munches the last two or three segments, she is milking the grub after a fashion; by means of the pressure, which favours the paralysis of the abdomen, she makes the rectal humour flow into the pocket, which she then rips open in order to sip the contents.