These trees grow on the Upper Amazon and Rio Negro in the dry virgin forest, where they occur in small scattered groves. This species is of great importance to the Indian of the Rio Negro. With its stem he constructs his “gravatána” or blowing tube, which, with the little arrows before described as made from the spines of the Patawá, forms a most valuable weapon, enabling him to bring down monkeys, parrots and curassow birds from their favourite stations on the summits of the loftiest trees of the forest. When he wishes to make a “gravatána” he searches in the forest till he finds two straight and tall stems of the “Pashiúba miri” of such proportionate thicknesses that one could be contained within the other. When he returns home he takes a long slender rod which he has prepared on purpose, generally made of the hard and elastic wood of the “Pashiúba barriguda,” and with it pushes out the pith from both the stems, and then with a little bunch of the roots of a tree fern, cleans and polishes the inside till the bore becomes as hard and as smooth as polished ebony. He then carefully inserts the slenderer tube within the larger, placing it so that any curve in the one may counteract that in the other. Should it still be not quite correct, he binds it carefully to a post in his house till it is perfectly straight and dry. He then fits a mouth-piece of wood to the smaller end of the tube, so that the arrow may go out freely at the other; and when he wishes to finish his work neatly, winds spirally round it from end to end, the shining bark of a creeper. Near the lower extremity he forms a sight with the large curved cutting tooth of the Paca (_Cœlogenus paca_), which he fixes on with pitch, and the gravatána is then fit for use.