Besides these particular aphides, which leave the nest directly after leaving the egg, there are four or five other species which live in it altogether, and feed on the roots of various growing plants. Some nests which I had contained a few, but under natural conditions they are to be found, I believe, in abundance. Special chambers, it would seem, are given up to them, and in Kirby’s _Marvels of Ant Life_ there is a picture of such a “subterranean cow-house.” The question arises, where do these aphides lay their eggs, and, if in the nest, does not it largely discount the intelligence, or prudence, attributed to _Lasius flavus_ in bringing the other ones into it? In that case, since the eggs of the various species probably resemble one another, any found outside would be brought in by the ants, just as their own larvæ or pupæ would be—or anything else which they value—nor need we ascribe greater foresight to the one act than to the other. Ants, however, do more wonderful things in relation to aphides than this that Sir John Lubbock has recorded, and if that act is unexampled, as an exhibition of prudence, elsewhere in the animal kingdom, it is not, I think, in this particular branch of it. First it must be remarked that amongst the aphides we have what is called the “alternation of generations,” that is to say a light-loving generation that feeds on the stems and leaves of upper earth, produces one that loves darkness, whose food is only the underground roots of the plants their parents lived on. This brood in its turn gives birth to another, which forthwith seeks the sun, and so the round goes on. There is this difference in the two broods, that the light-lovers, nevertheless, seek out darkness when the time comes to lay their eggs, whilst the children of darkness lay theirs in the caves where they have, all their lives, lived. That ants should be aware of all this, and habitually adapt their cow-keeping economy to circumstances so recondite, seems very extraordinary, but it would certainly appear to be the case. Thus when _Lasius fuliginosus_ (another Franco-Britannico, etc., species) sees _Schizoneura venusta_—its particular Aphis—seated on a grass stem, and evidently wishing to lay her eggs, it knows at once what to do. Soft and large, with voluminous wings, such an insect is not well fitted for burrowing. She could hardly do it, in fact, so the ants, recognising this, begin to do it for her, and soon drive a tunnel leading down to the roots of the grass, through which they lead her, first, however, having clipped off her wings, which are now but a useless encumbrance.