

ANNULOSA : INSECTA. 225 



duties necessary for the preservation of the society, except 

 defending the nest, this being left to the soldiers. In other 

 cases, as many as three distinct orders, or ' castes,' of neuters 

 may be present in the same nest. 



Amongst the more singular of the habits and instincts of 

 Ants two may be mentioned the instinct of making slaves, 

 and that of milking, so to speak, the little Plant-lice (Aphides). 

 As regards the first of these, it is found that certain Ants 

 possess the extraordinary instinct of capturing the pupae of 

 other species of Ants, and bringing them up as slaves. The 

 relations between the masters and the slaves vary a good deal 

 in different species. In the case of Formica rufescens, for in- 

 stance, the masters are entirely dependent upon their slaves ; 

 the males and females do nothing except reproducing the 

 species, and the neuters perform no other labour except that 

 of capturing fresh slaves. The masters are, in this case, un- 

 able even to feed themselves, and their existence is main- 

 tained entirely by the devotion of the slaves. In Formica san- 

 guinea, on the other hand, the number of slaves is much 

 less, and both masters and slaves occupy themselves in per- 

 forming most of the duties necessary for the community. 

 The masters, however, go alone when on slave-making ex- 

 peditions, and in case of a migration, the masters carry the 

 slaves in their mouths. 



A second singular fact in the history of Ants is found in the 

 relations which subsist between them and the Aphides, or 

 Plant-lice. The Aphides secrete, or rather excrete, a peculiar 

 viscid and sweet liquid, by means of a gland, which is situated 

 towards the extremity of the abdomen, and communicates with 

 the exterior by two tubular filaments. Ants are extremely 

 fond of this excretion, and it is a well established fact that 

 the Aphides allow themselves to be milked, as it were, by the 

 Ants. For this purpose the Ant touches and caresses the ab- 

 domen of the Aphis with its antennae, whereupon the latter 

 voluntarily exudes a drop of the coveted fluid. Ordinarily the 

 Ants seek the Aphides upon plants, but it is asserted that, in 

 some cases, they keep Aphides, much in the same way as human 

 beings keep cows ; though this is probably partly imaginary. 



ORDER XI. STREPSIPTERA. Females without wings or feet, 

 parasitic. Males possessing the posterior pair of wings, which 

 are large, membranous, and folded longitudinally like a fan. 

 The anterior pair of wings rudimentary, represented by a pair 

 of singular twisted organs. Jaws abortive. 



The Strepsiptera constitute a small order, which includes 

 certain parasites of minute size, found on Bees and other 

 Hymenoptera. The female is a soft vermiform grub, without 



VOL. I. Q 



