Biological Notes

Abstract

THE AGRICULTURAL ANTS OF TEXAS.—Mr. H. C. McCopk has presented to the Academy of Natural Sciences of Philadelphia a memoir on the habits of these most curious and interesting ants (Myrmica molefaciens, Buckley = M. barbata, Smith). An abstract of the memoir will be found in Sheet 20 of the Proceedings of the above Academy (p. 299). The author encamped in the midst of a large number of the anthills during the summer of 1877, and carefully studied the habits of the inmates; the spot selected was in the neighbourhood of Austin, Texas, upon the tableland to the south-west of the Colorado River and its affluent, Barton Creek. The limestone rock here and there cropped up, the soil was black and tenacious, varying in depth from a few inches to three feet. The formicaries were very numerous, and were to be found along roads, in open fields, and in the very streets, paths, gardens, and yards of Austin; indeed, one was even seen in the stone-paved courtyard of an hotel. They are commonly flat circular clearings, hard and smooth; a few have low mounds in the centre, composed of bits of gravel of one or two grains' weight; the clearings vary in width from twelve to two or three feet. From each, roads three to seven in number, diverge into the surrounding herbage. These are often of great length, and during the working hours are thronged by the ants going and returning. The ants take their siesta during the meridian heat of the sun, generally stopping work about twelve, and not returning to it until two or three o'clock. The seeds collected were always taken from off the ground, they were chiefly seeds of small Euphorbiaceous and Rubiaceous plants, and of grasses. The ants proved to be true harvesters. The seeds were carried into the granaries through the central gates. They were shelled, and the hulls were carried out and deposited in refuse heaps, which, when carefully searched, yielded no perfect fruits. They seemed to be most fond of the grass called Aristida stricta, and it even seems possible that they sow this for themselves, though the author does not commit himself to this as a fact. The interior economy of the ant-hill is fully described. Here it may be noted that the ants are clever in attack, that their “sting” is as bad as a wasp's, and that they are so well versed in the science of war, that they would have been more than a match for Mr. McCook, had he not himself employed a small army (of two men) to fight with those ants that would fight with him while he was pulling their granaries, their nurseries, and their queen's palace to pieces, in order to let us know all about them. Prof. Leidy made some remarks on this paper, adding that he had studied the habits of an allied species (M. occidentalis) which he had met with during a summer in the Rocky Mountains. The habits of this species were very like those of the species described by Mr. McCook, but in addition Prof. Leidy mentioned that his species fostered a fine large Coccus for its saccharine production.