In this choice, upon which even transcendent knowledge could not improve, such an assembly of difficulties is splendidly resolved, that one asks if one be not the dupe of some involuntary illusion, and if preconceived theories have not obscured the reality of facts, in short, whether the pen has not described imaginary marvels. A scientific result is only solidly established when confirmed by experiments repeated in every possible way. Now let us submit to experimental proof the physiological operation taught us by Cerceris tuberculata. If it be possible to obtain artificially what the Hymenopteron obtained by her sting, i.e. abolition of movement, and long preservation of the victim in a state of perfect freshness; if it be possible to bring about this wonder with the Coleoptera hunted by the Cerceris, or with those possessing a like nervous centralisation, while one fails with those whose ganglia are far apart, one must admit, however exacting one may be in the matter of proof, that the Hymenopteron possesses in the unconscious inspirations of instinct the resources of sublime science. Let us see then what experiment shows. The manner of operation is very simple. With a needle, or, better still, with the point of a fine steel pen, we must introduce a tiny drop of some corrosive liquid into the thoracic motive centres, pricking the insect slightly at the jointing of the prothorax behind the first pair of feet. The liquid which I use is ammonia, but it is evident that any other liquid whose action is equally strong would produce the same results. The metal pen being charged with ammonia as it might be with a droplet of ink, I give the prick. The effects thus obtained differ enormously, according to whether the experiment be made upon species with thoracic ganglia near together or upon those where these same ganglia are far apart. With regard to the first category, my experiments were made on Scarabæus, S. sacer and S. longicollis; on a bronze Buprestis; and on weevils, especially that Cleonus hunted by the heroine of these observations. In the second category I have experimented on Caraboidea, Carabus, Procrustes, Chlœnius, Sphodrus, Nebria; Longicornia, Saperda, and Lamia; on Melasomes; Blaps, Scaurus, and Asida.