_Gäb-by-kal̈-lan-goö-rong_, Aborigines of the lowlands of Western Australia. _Martin_ of the Colonists. The specific term of _pyrrhonota_ having been given to a bird of this group by Vieillot, prior to the publication of the List of Australian Birds by Messrs. Vigors and Horsfield in the Linnean Transactions, as quoted above, I have been necessitated to furnish this species with a new appellation, and have selected that of _arborea_ as indicative of its habits; for in every part of Australia that I have visited, it invariably selects the holes of trees for the purpose of nidification. It is strictly a summer visitant to Van Diemen’s Land and all the southern portions of Australia, arriving in August and retiring northwards as autumn approaches. The Tree Martin is a familiar species, frequenting the streets of the towns in company with the Swallow. I observed it to be particularly numerous in the streets of Hobart Town, where it arrives early in September; the more southern and colder situation of the island rendering all migratory birds later in their arrival there. It breeds during the month of October in the holes of trees, making no nest, but laying its eggs on the soft dust generally found in such places: the eggs are from three to five in number, of a pinky white faintly freckled at the larger end with fine spots of light reddish brown; they are eight lines long by six lines broad. Its food consists of insects of various kinds, particularly a species of small black fly. Considerable difference exists both in size and in the depth of colouring of specimens killed in New South Wales, Swan River and Van Diemen’s Land; but as there exists no distinctive character of marking, I am induced to regard them as mere local varieties rather than as distinct species. The Van Diemen’s race are larger in all their admeasurements, and have the fulvous tint of the under surface and the band across the forehead much deeper than in those killed in New South Wales; individuals from the latter locality again exceed in size those from Western Australia. Specimens from Van Diemen’s Land have the forehead crossed by a fulvous band; head, back of the neck, back and scapularies glossy bluish black; wings and tail brown; rump and upper tail-coverts light fulvous; throat, sides of the neck and flanks light fulvous, with a narrow stripe of dark brown in the centre of each feather; centre of the abdomen nearly white; irides, bill and feet blackish brown. The figures in the opposite Plate, which are of the natural size, were taken from two of the varieties mentioned above; the upper one from a specimen killed in New South Wales, the other two from birds taken in Van Diemen’s Land. [Illustration: CHELIDON ARIEL: _Gould_. _J. Gould and H. C. Richter, del^t_ _C. Hullmandel Imp._ ] COLLOCALIA ARIEL, _Gould_. Fairy Martin.