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 meager account. One great cause of war is the plundering of ants' nests by the slave-making species. Observers all agree that, in the case of the so called Amazon slave-making ant, this plundering is effected by a united march of the whole army composing a nest, 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 afterward serve as guides to the marauding excursion. When the scouts have been successful in discerning a suitable nest to plunder, and have completed their strategical investigations of the locality to their satisfaction—the latter process being often a laborious one, as it has special reference to the entrances of the nest, which are purposely made difficult to find by their architects—they return to their own fortress. Forel has seen them then walk about on the surface of this underground fortress for a long time, as if in consultation, after which some of them entered and again came out leading the host of warriors; these streamed from all the gateways, and ran about tapping each other with their heads and antennæ. They then formed into a column, composed of between one and two thousand individuals, and set out in orderly march to pillage the nest which had been examined by the scouts. According to Lespès, the column is about five metres long and fifty centimetres wide, marches at the rate of a metre per minute, and, on account of the distance which may have to be traversed, the march sometimes lasts for more than an hour. When they arrive at their destination a fierce battle begins, which, after raging for a time with much slaughter on both sides, generally, though not invariably, ends in the robbers gaining an entry. A barricade conflict then takes place below-ground, and, if the attack proves successful, the slave making ants again stream out of the plundered nest, each ant carrying a stolen pupa. The Amazons can not climb, and this fact being known to the other ants, when they find that victory is on the side of the enemy, they devote themselves to saving what treasure they can by carrying their pupæ up the grasses and bushes surrounding the nest. When the marauders have obtained all the booty that they can, they set off on their homeward march, each carrying a pupa. They do not always follow the shortest road, but return exactly on the track by which they came, no doubt being guided entirely by the scent left on the ground from their previous march. When they arrive home they commit the pupæ to the care of the slaves. Forel found that a particular colony of slave-makers watched by him sent out forty-four marauding expeditions in thirty days, of which number twenty-eight were completely successful, nine partially so, and the remainder failures. The average booty obtained by a successful expedition was one thou-
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THE POPULAR SCIENCE MONTHLY.