No matter: considering the nature of the game, endowed with good wings for flying, the capture must take place with a suddenness that makes it hardly possible, I should say, to obtain paralysis unaccompanied by death. A Cerceris face to face with her clumsy Weevil, a Sphex grappling with the fat Cricket or the portly Ephippiger, an Ammophila holding her caterpillar by the skin of its neck, all three have an advantage over a prey which is too slow in its movements to avoid attack. They can take their time, select at their ease the mathematical spot where the sting is to penetrate, and lastly go to work with the precision of an anatomist probing with his scalpel the patient who lies before him on the operating-table. But with the Bembex it is a very different matter: at the least alarm, the game [[278]]nimbly makes off; and, once on the wing, it can defy its pursuer. The Wasp has to pounce upon her prey unawares, without considering how she shall attack or calculating her blows, just as the Goshawk does when hunting in the fallows. Mandibles, claws, sting, every weapon must be employed simultaneously in the fierce fray so as to put an end as early as possible to a contest in which the least hesitation would give the victim time to escape. If these conjectures are borne out by the facts, the Bembex’ prize can be nothing but a corpse or at most a mortally wounded prey.
Well, my conjectures are correct: the Bembex delivers her attack with a dash which would do credit to a bird of prey. To surprise the Wasp hunting is not an easy thing; were we never so well armed with patience, we should watch in vain in the neighbourhood of the burrow: the favourable opportunity would not present itself, for the insect flies far away and there is no possibility of following it in its rapid evolutions. Its tactics would doubtless be unknown to me but for the assistance of a utensil from which I would certainly never have expected such a service. I am speaking of my umbrella, which I used as a protection against the sun in the sand of the Bois des Issarts. [[279]]
I was not the only one to profit by its shade; I was generally surrounded by numerous companions. Gad-flies of various species would take refuge under the silken dome and sit peacefully on every part of the tightly-stretched cover. I was rarely without their society when the heat became overpowering. To while away the hours when I had nothing to do, it amused me to watch their great gold eyes, which shone like carbuncles under my canopy; I loved to follow their solemn progress when some part of the ceiling became too hot and obliged them to move a little way on.
One day, bang! The tight cover resounded like the skin of a drum. Perhaps an oak had dropped an acorn on the umbrella. Presently, one after the other, bang, bang, bang! Can some practical joker have come to disturb my solitude and fling acorns or little pebbles at my umbrella? I leave my tent and inspect the neighbourhood: nothing! The same sharp sound is repeated. I look up at the ceiling, and the mystery is explained. The Bembex of the vicinity, who all consume Gad-flies, had discovered the rich provender that was keeping me company and were impudently penetrating my shelter to seize the Flies on the ceiling. Things were going to perfection: I had only to sit still and look. [[280]]
Every moment a Bembex would enter, swift as lightning, and dart up to the silken ceiling, which resounded with a sharp thud. Some rumpus was going on aloft, where the eye could no longer distinguish between attacker and attacked, so lively was the fray. The struggle did not last for an appreciable time: the Wasp would retire forthwith with a victim between her legs. The dull herd of Gad-flies, at this sudden irruption which slaughtered them one after the other, drew back a little all round, without quitting the treacherous shelter. It was so hot outside! Why get excited?
Obviously, this suddenness of attack, followed by the swift removal of the prey, does not allow the Bembex to regulate her dagger-play. The sting no doubt performs its office, but it is directed without precision at those spots which the hazards of the fight place within its reach. I have seen Bembex, to finish off their half-killed Gad-flies still struggling in the assassin’s grasp, munch the head and thorax of the victims. This habit in itself proves that the Wasp wants a genuine corpse and not a paralysed prey, since she ends the Fly’s agony with so little ceremony. All things considered, therefore, I think that, on the one hand, the nature of the prey, which dries up so quickly, and, on the other hand, the difficulty of making such rapid [[281]]attacks, explain why the Bembex serve up dead prey to their larvæ and consequently cater for them from day to day.
Let us watch the Wasp as she returns to the burrow with her capture held under her abdomen between her legs. Here comes one, the Tarsal Bembex (B. tarsata), who arrives laden with a Bee-fly. The nest is situated at the sandy foot of a steep bank. The huntress announces her approach by a shrill humming, which has something plaintive about it and which continues until the insect sets foot to earth. We see the Bembex hover above the bank and then dip straight down, very slowly and cautiously, all the time emitting her shrill hum. Should her keen eye descry anything unusual, she slackens her descent, hovers for a second or two, goes up again, comes down again and flies away, swift as an arrow. After a few moments, here she is once more. Hovering at a certain height, she appears to be inspecting the locality, as if from the top of an observatory. The vertical descent is resumed with the most cautious slowness; finally, the Wasp alights with no hesitation whatever at a spot which to my eye has naught to distinguish it from the rest of the sandy surface. At that instant the plaintive whimper ceases.
The insect, no doubt, has landed more or [[282]]less on chance, since the most practised eye cannot distinguish one spot from the other on that expanse of sand; it has alighted somewhere near its home, of which it will now seek the entrance, concealed after its last exit not only by the natural falling-in of the materials but also by the Wasp’s own careful sweeping. But no: the Bembex does not hesitate at all, does not grope about, does not seek. By common consent the antennæ are looked upon as organs for guiding insects in their searches. At this moment of the return to the nest, I see nothing particular in the play of the antennæ. Without once letting go her prey, the Bembex scratches a little in front of her, at the very spot where she has alighted, gives a push with her head and straightway enters, with the Fly under her abdomen. The sand falls in, the door closes and the Wasp is at home.
It makes no difference that I have seen the Bembex return to her nest hundreds of times; it is always with fresh astonishment that I behold the keen-sighted insect find without hesitation a door whose presence there is nothing to indicate. This door, in fact, is hidden with jealous care, not now, after the Bembex has gone in—for the obliterating sand does not become quite level of its own weight, but leaves perhaps a slight depression, or an incompletely [[283]]blocked porch—but certainly after she comes out, for, when starting on an expedition, she never fails to put a finishing touch to the result of the natural landslip. Wait for her departure and you shall see her, before flying off, sweep the front of the door and level it with scrupulous care. When she is gone, I defy the most penetrating eye to find the entrance. To discover it again, when the sandy expanse was of any size, I had to resort to a kind of triangulation; and how often, after a few hours’ absence, did not my combinations of triangles and my efforts of memory prove to be at fault! All that remained was the stake, a grass-stalk planted on the threshold; and even this method was not always effective, for the insect, with its passion for continually improving the outside of the nest, often made the bit of straw disappear from sight. [[284]]