Bates has given a vivid description of the armies of the South American Foraging Ants (_Eciton_). They are carnivorous hunters who march in large armies, and are found on the banks of the Amazon, especially in the open campos of Santarem. The _Eciton legionis_ chiefly carry off the mangled larvae and pupae of other ants. They will attack the nests of a bulky species of the genus _Formica_; they lift out the bodies of these ants and tear them in pieces, as they are too large for a single _Eciton_ to carry off, a number of carriers seizing each fragment. They seem to divide into parties, one party excavating and the other carrying away the grains of earth to a distance from the hole just sufficient to prevent them rolling back into it. There is, however, no rigid distribution of labour, the miners sometimes becoming carriers, and then again assuming the office of carrying off the prey. In marching off they form a broad and compact column, sixty or seventy yards in length, those who may be empty-handed assisting heavily-laden comrades. The _Eciton drepanophora_ attacks and carries off all kinds of insects, especially wingless species, such as maggots, caterpillars, larvae of cockroaches, etc. An eyeless species,[33] the _Eciton erratica_, rapidly forms covered passages under which to advance, and shows great skill in fitting the keystone to these convex arcades.[34] [33] Belt points out that blindness is an advantage in the particular mode of hunting adopted by these ants, enabling them to keep together. Those species of _Eciton_ which hunt singly have very well developed eyes. [34] Bates, _Naturalist on the Amazons_ (edition of 1892), pp. 355-363. Belt has also made some extremely interesting observations on the _Ecitons_, whom for intelligence he places first among the ants of Central America, and as such at the head of the Articulata.[35] [35] See _Naturalist in Nicaragua_, 1888, pp. 17-29. _Expeditions to acquire slaves._--In order to reduce one's own species to slavery, it seems at first that an intelligence is required as developed as that of Man. It is necessary in fact to attack beings nearly equally well endowed from an intellectual and physical point of view. The enterprise evidently presents every possible difficulty; but in case of success, the result more than compensates for the effort. The master in future need not trouble to work, for he possesses a tool capable of doing everything as well as himself, since by means of language he can easily impress his will on the acts of the other; a domestic animal is only an auxiliary, the slave entirely replaces his owner in every labour.