CHAPTER XVI.
THE NATURALIST ON THE AMAZON.
On the 16th of January, the dry season came abruptly to an end. The sea-breezes, which had been increasing in force for some days, suddenly ceased, and the atmosphere became misty: at length, heavy clouds collected where a uniform blue sky had for many weeks prevailed, and down came a succession of heavy showers, the first of which lasted a whole day and night. This seemed to give a new stimulus to animal life. On the first night, there was a tremendous uproar,—tree-frogs, crickets, goat-suckers, and owls, all joining to perform a deafening concert. One kind of goat-sucker kept repeating at intervals, throughout the night, a phrase similar to the Portuguese words, 'Joao corta pao,'—'John, cut wood;' a phrase which forms the Brazilian name of the bird. An owl in one of the trees muttered now and then a succession of syllables resembling the word 'murucututu.' Sometimes the croaking and hooting of frogs and toads were so loud, that we could not hear one another's voices within doors. Swarms of dragon-flies appeared in the day-time about the pools of water created by the rain; and ants and termites came forth in great numbers."
ANTS.
This region is the very headquarters and metropolis of ants. There are numerous species, differing in character and habits, but all of them at war with man, and the different species with one another. Our author thus relates his observations of the saüba-ant:—
"In our first walks, we were puzzled to account for large mounds of earth, of a different color from the surrounding soil, which were thrown up in the plantations and woods. Some of them were very extensive, being forty yards in circumference, but not more than two feet in height. We soon ascertained that these were the work of the saübas, being the outworks, or domes, which overlie and protect the entrances to their vast subterranean galleries. On close examination, I found the earth of which they are composed to consist of very minute granules, agglomerated without cement, and forming many rows of little ridges and turrets. The difference of color from the superficial soil is owing to their being formed of the undersoil brought up from a considerable depth. It is very rarely that the ants are seen at work on these mounds. The entrances seem to be generally closed: only now and then, when some particular work is going on, are the galleries opened. In the larger hillocks, it would require a great amount of excavation to get at the main galleries; but I succeeded in removing portions of the dome in smaller hillocks, and then I found that the minor entrances converged, at the depth of about two feet, to one broad, elaborately worked gallery, or mine, which was four or five inches in diameter.
"The habit of the saüba-ant, of clipping and carrying away immense quantities of leaves, has long been recorded in books of natural history; but it has not hitherto been shown satisfactorily to what use it applies the leaves. I discovered this only after much time spent in investigation. The leaves are used to thatch the domes which cover the entrances to their subterranean dwellings, thereby protecting from the deluging rains the young broods in the nests beneath. Small hillocks, covering entrances to the underground chambers, may be found in sheltered places; and these are always thatched with leaves, mingled with granules of earth. The heavily-laden workers, each carrying its segment of leaf vertically, the lower end secured by its mandibles, troop up, and cast their burthens on the hillock; another relay of laborers place the leaves in position, covering them with a layer of earthy granules, which are brought one by one from the soil beneath.
"It is a most interesting sight to see the vast host of busy, diminutive workers occupied on this work. Unfortunately, they choose cultivated trees for their purpose, such as the coffee and orange trees."