That the insect, finding itself in this mixed assembly, should rip open what is still inanimate matter and respect what is already a cradle, that it should discriminate between the lawful and the unlawful, in circumstances such as these, seems to me incapable of explanation, if there be no guide but senses resembling our own. It is useless to say that it is a case of sight: the Beetle works in absolute darkness. Even if she worked in the light, that would not lessen the difficulty. The shape and appearance of the pill are alike in both instances; the clearest sight would be at fault once the pills were mixed up. It is impossible to suggest that smell has anything to do with it: the substance of the pill does not vary; it is always the produce of the Sheep. Impossible likewise to say that she is exercising the sense of touch. What delicacy of touch can there be under a coat of horn? Besides, the most exquisite sensitiveness would be required. Even if we admit that the insect’s feet, particularly the tarsi, or the palpi, or the antennæ, or anything you please, possess a certain faculty for distinguishing between hard and soft, rough and smooth, round and angular, still our experiment with the Sacred Beetle’s sphere warns us to look where we are going. There surely we had the exact equivalent of the Copris’ sphere—made of the same materials, kneaded to the same consistency, given the same outline—and yet the Copris makes no mistake. To drag the sense of taste into the problem would be absurd. There remains that of hearing. Later on, I might not deny the possibility that this has something to do with it. When the larva is hatched, the mother, ever attentive, might conceivably hear it nibbling the wall of the cell, but for the present the chamber contains merely an egg; and an egg is always silent. Then what other means does the mother possess, I will not say of thwarting my machinations—the problem is on a loftier plane and animals are not endowed with special aptitudes in order to dodge an experimenter’s wiles—what other means does she possess of obviating the difficulties attendant upon her normal labours? Do not lose sight of this: she begins by shaping a sphere; and the globular mass often does not differ from the pills that have received the egg, in respect of either form or size. Nowhere is there peace, not even below ground. When, in a moment of panic, the too-timid mother falls off her sphere and forsakes it to seek refuge elsewhere, how can she afterwards find her ball again and distinguish it from the others, without running the risk of crushing an egg when she is pressing in the top of a pill to make the necessary crater? She needs a safe guide here. What is that guide? I do not know.