_Wars._--On the wars of ants a great deal might be said, as the facts of interest in this connection are very numerous; but for the sake of brevity I shall confine myself to giving only a somewhat meagre account. One great cause of war is the plundering of ants' nests by the slave-making species. Observers all agree that this plundering is effected by a united march of the whole army composing a nest of the slave-making species, directed against some particular nest of the species which they enslave. According to Lespès and Forel, single scouts or small companies are first sent out from the nest to explore in various directions for a suitable nest to attack. These scouts afterwards serve as guides to the marauding excursion. Forel saw several of these scouts of the species _F. rufescens_ or Amazon carefully inspecting a nest of _F. fusca_ which they had found, investigating especially the entrances. These are purposely made difficult to find by their architects, and it not unfrequently happens that after all precautions and inspections on the part of the invaders, an expedition fails on account of not finding the city gates. When the scouts have been successful in discovering a suitable nest to plunder, and have completed their strategical investigations of the locality to their satisfaction, they return straight to their own nest or fortress. Forel has then seen them walking about on the surface of their nest for a long time, as if in consultation, or making up their minds. Then some of them entered the nest, soon after which hosts of warriors streamed out of the entrances, and ran about tapping each other with their heads and antennæ. They then formed into column and set out to pillage the nest of the slave ants. The following is the account which Lespès gives of such expeditions:--