Its powers of flight are fully adequate and in every way adapted to the extensive plains it is destined to inhabit, enabling it readily to pass, frequently at a great height in the air, from one part of the plain to another. Its flight is, however, performed with a motion of the wings totally different from that of any other member of the great family of _Psittacidæ_ I have seen, and has frequently reminded me of the heavy flapping manner of the Pewit, except that the flapping motion was even slower and more laboured, like that of the Terns. It has a loud screeching piercing cry, which it frequently utters during flight. Its food consists of berries, the fruits of a species of _Loranthus_, and the pollen of flowers, to which is added a species of scaly bug-like insect, which infests the branches of its favourite trees; in all probability small caterpillars also form a part, as I have found them in the crops of several of the _Platycerci_. It breeds in the holes of the large Eucalypti growing on the banks of rivers; the eggs, which are white, being four or five in number, about an inch and an eighth long by seven-eighths broad. The sexes, as will be seen in the accompanying Plate, differ very considerably in the colouring of their plumage; the young males during the first two years cannot be distinguished from the female, except by dissection. The male has the head and back of the neck verditer green; throat, all the under surface, edge of the shoulder and upper tail-coverts bright yellowish green; back black; rump lazuline blue; wing-coverts deep rich crimson-red; scapularies dark green, tipped with black; primaries black at the base, with the external webs and the apical portion of the inner webs deep green; secondaries black, edged with deep green, and one or two with a tinge of red at the tip; tail green above, passing into yellow at the tip, the extreme end fringed with pink; under surface of the tail black, tipped with yellow and pink as above; irides reddish orange in some, scarlet in others; bill rich orange-scarlet; feet olive-brown. The female has the head and upper surface dull green; under surface dull yellowish green; a few of the wing-coverts crimson-red, forming a stripe down the wing; rump pale verditer blue; tail-feathers more largely tipped with pink than in the male; irides olive-brown; bill light horn-colour. The Plate represents the two sexes of the natural size. [Illustration: PLATYCERCUS SEMITORQUATUS. _J. Gould and H.C. Richter del et lith._ _C. Hullmandel Imp._ ] PLATYCERCUS SEMITORQUATUS, _Quoy and Gaim._ Yellow-collared Parrakeet. _Psittacus semitorquatus_, Quoy and Gaim. _Dȍw-arn_, Aborigines of the lowland districts of Western Australia. _Dȕm-ul-uk_, Aborigines of the mountain districts of Western Australia. _Twenty-eight Parrakeet_, Colonists of Swan River.