As a matter of fact, the hereditary transmission of a contracted habit is effected in an irregular and far from precise manner, supposing it is ever really effected at all. But the whole difficulty comes from our desire to express the knowledge of the hymenoptera in terms of intelligence. It is this that compels us to compare the Ammophila with the entomologist, who knows the caterpillar as he knows everything else--from the outside, and without having on his part a special or vital interest. The Ammophila, we imagine, must learn, one by one, like the entomologist, the positions of the nerve-centres of the caterpillar--must acquire at least the practical knowledge of these positions by trying the effects of its sting. But there is no need for such a view if we suppose a _sympathy_ (in the etymological sense of the word) between the Ammophila and its victim, which teaches it from within, so to say, concerning the vulnerability of the caterpillar. This feeling of vulnerability might owe nothing to outward perception, but result from the mere presence together of the Ammophila and the caterpillar, considered no longer as two organisms, but as two activities. It would express, in a concrete form, the _relation_ of the one to the other. Certainly, a scientific theory cannot appeal to considerations of this kind. It must not put action before organization, sympathy before perception and knowledge. But, once more, either philosophy has nothing to see here, or its rôle begins where that of science ends.