From one point of view instinct appears to be a degradation rather than a perfecting of intelligence, because the acts which proceed from it are neither so spontaneous nor so personal; but from another point of view they are much better executed, with less hesitation, with a slighter expenditure of cerebral force and a minimum of muscular effort. A habitual act costs us much less to execute than a deliberate and reflective act. It is thus that the constructions of bees are more perfect than those of ants; the former act by instinct, the latter reason their acts at each step. _Instinctive actions originate in reflective actions._--No doubt it may be said: It is a pure hypothesis thus to consider instinct as derived from intelligence; why not admit as well that instinctive acts have been such from the beginning--in other words, that species have been created such as we see them to-day? The preceding explanation, however, has the advantage of being in harmony with the general theory of evolution, which, whether true or not, so well explains the most complicated facts that for the present it must be accepted. For the rest, if it is not possible to appraise the psychic faculties possessed by the ancestors of existing animals we may at least observe certain facts which put us on the road of explanation. An interesting member of the Hymenoptera, the _Sphex_, assures food for the early days of the life of its larvae in a curious way.[7] Before laying its eggs it seizes a cricket, paralyses it with two strokes of its sting--one at the articulation of the head and the neck, the other at the articulation of the first ring of the thorax with the second--each stab traversing and poisoning a nervous ganglion. The cricket is paralysed without being killed; its flesh does not putrefy, and yet it makes no movement. The _Sphex_ places an egg on this motionless prey, and the larva which emerges from it devours the cricket. Here assuredly is a marvellous and certain instinct. One cannot even object that the strokes of the sting are inevitably directed to these points because the chitinous envelope of the victim offers too much resistance in other spots for the dart to penetrate, because here is the _Ammophila_, a near relative of the _Sphex_, which chooses for its prey a caterpillar. It is free to introduce its sting into any part of the body, and yet with extreme certainty it strikes the two ganglions already mentioned.[8] [7] "Etude sur l'Instinct et les Metamorphoses des Sphegiens," _Ann. Sc. Nat._, iv. Serie, t. 6, 1856. [8] P. Marchal, "Observations sur _l'Ammophila affinis_," _Arch. de Zool. exper. et gener._, ii. Serie, t. 10, 1892.