Still it seems quite possible that this failure may have been due to my not having allowed the ants sufficient time to swallow their food, as I killed them almost immediately after disturbing them at their meal. After having twice observed the ants eating as above described, I made some experiments in feeding them myself. They immediately seized and set to work upon a minute ball of flour which I cut out from the centre of a grain of millet, taken from a heap in front of a nest of _A. structor_, which had begun to sprout and been deprived of its radicle and dried. A similar ball taken from a sprouting grain of millet, but the growth of which had not been arrested, was also partially eaten; but the hard, dry flour taken from a grain of the same in its natural state, not moistened, was at once rejected and thrown on the rubbish heap. The fat, oily seed leaves of the hemp, however, were eagerly taken, though not softened by water, their peculiar texture allowing the ants to scrape off particles, as in the case of the ball of flour of the sprouted millet. Under ordinary circumstances the hard shell of the hemp-seed, and the coats of most other small fruits, grain, and seeds, would prevent the ants from getting at the contents while dry, but in the earliest stage of sprouting the shell parts of itself, allowing the radicle to protrude, and then they find their opportunity. (See Figs. A, A 2, Plate VI., p. 35.) It has always been supposed that ants, from the delicate nature of their mouth organs, were only able to lap up liquids or to swallow very soft animal tissues, and one of the great difficulties in the way of admitting that they might collect seeds for food, lay in the apparent impossibility of their eating such hard substances. But it has generally been overlooked that not only are all seeds soft when moistened with water and ready to grow, but also that there are certain kinds of seeds the contents of which are naturally soft. The most important organs in an ant's mouth are shown in Fig. D 2, and D 3, in Plate I., p. 21. D 3 represents one of the horny, toothed mandibles, which serve admirably for scraping off particles of flour from the seeds. Within these are the parts shown at D 2, where the outermost pieces are the maxillæ and their four-jointed palpi or feelers, and the innermost piece the labium and its three-jointed palpi, between which the end of the delicate membranous tongue appears.