Page:Popular Science Monthly Volume 3.djvu/27

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17
INSTINCT IN INSECTS.

ject, and reached it. This was the nest of another species of ants, blackish-gray ones, whose hill rose in the grass twenty steps from the hedge. A few blackish-gray ones were scattered about the hill; as soon as these perceived the enemy, they darted upon the stranger, while others hurry into the galleries to give the alarm. The besieged ants come out in a body. The assailants dash upon them, and, after a very short but very spirited struggle, drive the black-gray ones back to the bottom of their holes. One army corps presses after them into the galleries, while other groups labor to make themselves an opening with their teeth into the lateral parts of the hill. They succeed, and the remainder of the troop makes its way into the besieged city by the breach. Peter Huber had seen battles and exterminations of ants before this; he supposed they were slaughtering each other in the depths of the caverns. What was his amazement, after three or four minutes, when he saw the assailants issue hurriedly forth again, each holding between its mandibles a larva or a nympha of the conquered tribe! The aggressors took exactly the same road again by which they had come, passed through the hedge, crossed the road, at the same place, and made their way, still loaded with their prey, toward a field of ripe grain, into which the honest citizen of Geneva, respecting another's property, refrained, with regret, from following them.

This expedition, worthy of the annals of barbarian piracy, inspired Huber with an amazement easy to understand. He examined, and discovered, to his great surprise, that some ant-hills were inhabited in common by two kinds of ants, forming two castes. He designates one of these by the name of "amazon or legionary ants; a name strongly suggesting their martial character," he says. The others he calls, very justly, "auxiliaries." The amazons do not work; their duty is fighting and carrying off the nymphæ and larvæ. They choose the hour toward sunset for their warlike raids against the industrious and peaceable tribes of the neighborhood. Whenever the weather is fine, they sally out thus, and levy their tribute of flesh. The auxiliaries, for their part, are employed in all internal duties, and in keeping up and repairing the dwelling. They alone open and close the entrance to the ant-hill, night and morning; they alone (in the species observed by P. Huber) go after provisions, for they feed the whole establishment, even the legionaries, which are idle except when on their forays; they rear with equal care the larvæ of the legionaries and those that are stolen; they alone, in fine, seem to decide upon the material interests of the community, the requisite enlargements, the need of emigration, and the place suitable for it. Peter Huber made one experiment that shows very plainly the absolute dependence of the amazons upon their associates. These fierce warriors do not understand any household work. Huber put thirty amazons into a glazed drawer, covered, with earth on the bottom, with a certain number of larvæ and of nymphæ, both of their own kind and of the auxiliary species. A little