You tell me that instinct is an acquired habit, that a casual circumstance, propitious to the animal’s offspring, was the first to prompt it. Let us look into the thing more closely. If I understand aright, we must suppose some Ammophila, in a very remote past, to have accidentally injured her caterpillar’s nervous centres; to have found herself the gainer by this operation, both as regards herself, in being released from a struggle not unattended with danger, and as regards her larva, thus supplied with fresh, living and yet harmless victuals; and consequently to have endowed her offspring, by heredity, with a natural tendency to repeat the advantageous device. The maternal legacy did not benefit all the descendants equally: some were poor hands at the newborn art of the stiletto; others were adepts. Then came the struggle for existence, the hateful væ victis! The weak went under, the strong flourished; and, as age succeeded age, selection by vital competition changed the fleeting impression of the start into a deep-rooted, ineffaceable impression, exemplified in the masterly instinct which we admire in the Wasp to-day. Well, I avow, in all sincerity, this is asking a little too much of chance. When the Ammophila first found herself in the presence of her caterpillar, there was nothing, you would have it, to guide the sting. The choice was made at random. The pricks were directed at the upper surface of the captured prey, at the lower surface, at the sides, the front and the back indiscriminately, according to the fortunes of a close struggle. The Hive-bee and the Social Wasp sting those points which they are able to reach, without showing a preference for one part over the other. That is how the Ammophila must have acted, when still ignorant of her art.