Just as in the case of the aphides released by _Lasius fuliginosus_, these ants will never see their butterflies again, nor will they gain any after advantage that can with certainty be traced to the particular individuals thus set free. But they gain in such a manner as, if the reflection really occurred to them, would make ants not much below men. The process of reasoning would be this: “Though we may very likely not get any caterpillars from the eggs which these butterflies will lay, yet we ought not to kill them, because then there would be so many butterflies less in the world, to lay eggs, and if we did this every year, and other ants too, caterpillars, as well as butterflies, would become scarce, and at last we should not get enough.” For myself I doubt if ants really do reason like this, but by what steps this habit of releasing butterflies so as to ensure the perpetuation of the species has come about, I don’t quite see. In the case of the aphides, perhaps it has been through actual observation of their habits, and here, too, this hypothesis may not be excluded, since the butterflies might well be seen laying their eggs, nor is it unlikely that these are watched, and the issuing caterpillars tended from the beginning. For the purposes of the ants, indeed, all aphides, and every theophrastus, would be the same, and they might very well think that those which they found laying, or about to lay their eggs, were the very ones previously liberated by them from the nest. Thus the difficulty involved in supposing that they must reason in a general and not merely in a particular way does not really exist. Some of these black caterpillar-tending ants of India are not always so lucky as to secure stock. They may live far from a _jujube_ tree, and so never meet the right species; but if ever they do, even though it be in the most unexpected manner, they are not taken by surprise, notwithstanding that other caterpillars are habitually devoured by them. Mrs. Wyllie proved this by an experiment. “I took Theophrastus,” she tells us, “from a tree, and introduced him on the pathway of another company of the same species of ant, which lived in our verandah, but kept no farm, and it was odd to see the ants come tumbling out headlong to fight the intruder, and the sudden way in which they cooled down on investigation of the foe. None attempted to harm him, and he was politely escorted across the boundary, the ants running alongside and feeling him all over with their antennæ. This must have been instinctive, as they could have had no former knowledge of him as a ‘milk-giver.’” Mrs. Wyllie adds that “the dead chrysalids in an ants’ nest are carefully removed and thrown away outside; the ants also distinguish between the dead and the living.”