(syn. Petrochelidon Ϯ Tree Martin P. nigricans) Gr. ὑλη hulē woodland, forest; χελιδων khelidōn, χελιδονος khelidonos swallow; "Genus HYLOCHELIDON, Gould. I have not instituted a new generic appellation for the following bird without maturely considering the propriety of so doing, after carefully comparing it with the various forms already characterized of this extensive family; which, whenever it may be monographed by a scientific ornithologist, will be found to comprise ample materials for the formation of more genera than has yet been proposed, as well as numerous species with which we are at present unacquainted; and I have no doubt that Mr. Blyth's notion of dividing them into sections in accordance with the forms of their nests will be found a very happy suggestion—saucer-builders, retort-builders, bank-burrowers, builders in the holes of trees, &c. The species of this form are part of a small section of the Swallows which nidify in the holes of trees, without any nest for the deposition of their delicate eggs. Their bare tarsi at once separate them from the Chelidons, and they also differ from the American Petrochelidons. ... Sp. 55. HYLOCHELIDON NIGRICANS. TREE SWALLOW. Chelidon arborea, Gould, Birds of Australia, vol. i. Introd. p. xxix. ... Dun-rumped Swallow, Lath. Gen. Hist., vol. vii, p. 309. ... Gab-by-kal-lan-goo-rong, Aborigines of the lowlands of Western Australia. Martin of the Colonists." (Gould 1865); "Hylochelidon Gould, 1865, Handb. Birds Austral., 1, p. 110. Type, by monotypy, Hirundo nigricans Vieillot." (Peters 1960, IX, 118).