What ought the powerful Cetonia-grub to do to defy the Two-banded Scolia, who is far less vigorous than her victim? It should imitate the Anoxia-larva and remain rolled up like a Hedgehog until the enemy retires. It tries to escape, unrolls itself and is lost. The other does not stir from its posture of defence and resists successfully. Is this due to acquired caution? No, but to the impossibility of doing otherwise on the slippery surface of a table. Clumsy, obese, weak in the legs, curved into a hook like the common White Worm (The larva of the Cockchafer.--Translator's Note.), the Anoxia-larva is unable to move along a smooth surface; it writhes laboriously, lying on its side. It needs the shifting soil in which, using its mandibles as a plough-share, it digs into the ground and buries itself.
Let us try if sand will shorten the struggle, for I see no end to it yet, after more than an hour of waiting. I lightly powder the arena. The attack is resumed with a vengeance. The larva, feeling the sand, its native element, tries to escape. Imprudent creature! Did I not say that its obstinacy in remaining rolled up was due to no acquired prudence but to the necessity of the moment? The sad experience of past adversities has not yet taught it the precious advantage which it might derive from keeping its coils closed so long as danger remains. For that matter, on the unyielding support of my table, they are not one and all so cautious. The larger seem even to have forgotten what they knew so well in their youth: the defensive art of coiling themselves up.
I continue my story with a fine-sized specimen, less likely to slip under the Scolia's onslaught. When attacked, the larva does not curl up, does not shrink into a ring as did the last, which was younger and only half as large. It struggles awkwardly, lying on its side, half-open. For all defence it twists about; it opens, closes and reopens the great hooks of its mandibles. The Scolia grabs it at random, clasps it in her shaggy legs and for nearly a quarter of an hour battles with the luscious tit-bit. At last, after a not very tumultuous struggle, when the favourable position is attained and the propitious moment has come, the sting is implanted in the creature's thorax, in a central point, below the throat, level with the fore-legs. The effect is instantaneous: total inertia, except of the appendages of the head, the antennae and mouth-parts. I achieved the same results, the same prick at a definite, invariable point, with my several operators, renewed from time to time by some lucky cast of the net.
Let us mention, in conclusion, that the attack of the Interrupted Scolia is far less fierce than that of the Two-banded Scolia. The Wasp, a rough sand-digger, has a clumsy gait; her movements are stiff and almost automatic.
She does not find it easy to repeat her dagger-thrust. Most of the specimens with which I experimented refused a second victim on the first two days after their exploits. As though somnolent, they did not stir unless excited by my teasing them with a bit of straw. Although more active and more ardent in the chase, the Two-banded Scolia likewise does not draw her weapon every time that I invite her. For all these huntresses there are moments of inaction which the presence of a fresh prey is powerless to disturb.
The Scoliae have taught me nothing further, in the absence of subjects belonging to other species. No matter: the results obtained represent no small triumph for my ideas. Before seeing the Scoliae operate, I said, guided solely by the anatomy of the victims, that the Cetonia-, Anoxia- and Oryctes-larvae must be paralysed by a single thrust of the lancet; I even named the point where the sting must strike, a central point, in the immediate vicinity of the fore-legs. Of the three genera of paralysers, two have allowed me to witness their surgical methods, which the third, I feel certain, will confirm. In both cases, a single thrust of the lancet; in both cases, injection of the venom at a predetermined point. A calculator in an observatory could not compute the position of his planet with greater accuracy. An idea may be taken as proved when it attains to this mathematical forecast of the future, this certain knowledge of the unknown.
When will the acclaimers of chance achieve a like success? Order appeals to order; and chance knows no laws.
