it, therefore, be absolutely necessary to the ants or their economy, any more than a species of Aphis which I found numerous in some nests, while in others I observed a Staphylinus (Astilbus caniculatus, Dillwyn); and the first capture which I made in the ants' nests at Mickleham, and supposed to be the Claviger, I found on examination was a species of Euplectus, apparently undescribed: from the two latter insects the ants probably procure no exudation, but they are notorious for obtaining it from the different species of Aphis.—From another insect, the Atemeles acuminatus, Kirby, I have no doubt a similar fluid is obtained by more than one species of ant. Some years ago I was watching the proceedings of a colony of the Formica rufa, or wood-ant, and, on scattering a small portion of the nest down a sloping bank, I observed a specimen of Atemeles amongst the ants, running quickly about until seized by one of them; I searched in vain for more; but in the nest of Formica fusca I have frequently found them, and two years ago, whilst attentively watching the proceedings of that species, about the first week in May, just when the young larvae are found, I observed an ant carrying an Atemeles in its mouth towards the nest; I searched further, and detected twelve or fourteen ants thus employed, and I found them very reluctant to part with their burthens: the Atemeles, like the Claviger, is furnished with tufts of hairs, but they are situated on the lateral margins of the first three or four segments of the abdomen; there are also two processes flocked with hair on the ventral segments; this is perhaps an adaptation to the same purpose, as mentioned by Müller with regard to Claviger: in the Astilbus caniculatus before mentioned the tufts are wanting, still the same end may possibly be attained by another means.
The affection of the ants for these little creatures is very great; for on removing a large stone from a nest of F. flava, full of eggs, larvae and pupae, I immediately observed several specimens of Claviger, one pair in copulâ, others crawling sluggishly amongst the larvæ, &c, the ants apparently taking no heed of them: I placed one on the turned up stone, on which several ants were running; it was instantly seized, and carried to the nest: I have tried the same experiment with Atemeles with the same result, but I have also seen the Atemeles attempt to escape from the nest, pursued, and taken back; this, from its blindness and sluggish motions, I should expect is never the case with Claviger. I am inclined to the opinion that the only purpose for which these insects are retained by the ants, is for the sake of the fluid which they extract from them; I feel convinced that there are
