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. CHAPTER 13. THE METHOD OF THE CALICURGI. The non-armoured victims, vulnerable by the sting over almost their whole body, ordinary caterpillars and Looper caterpillars, Cetonia- and Anoxia-larvae, whose only means of defence, apart from their mandibles, consists of rollings and contortions, called for the testimony of another victim, the Spider, almost as ill-protected, but armed with formidable poison-fangs. How, in particular, will the Ringed Calicurgus set to work in operating on the Black-bellied Tarantula, the terrible Lycosa, who with a single bite kills the Mole or the Sparrow and endangers the life of man? How does the bold Pompilus overcome an adversary more powerful than herself, better-equipped with virulent poison and capable of making a meal of her assailant? Of all the Hunting Wasps, none risks such unequal conflicts, in which appearances would proclaim the aggressor to be the victim and the victim the aggressor.