Humanity had evidently deposited its larva in the vicinity.

The care with which an insect selects a certain flower or fruit, or piece of flesh, or the way in which the ichneumon seeks the larva of a strange insect so that it may lay its eggs in that particular place only, and to secure which it fears neither labour nor danger, is obviously very analogous to the care with which a man chooses a woman of a definite nature individually suited to him.