That the gradual investigation of the interior of Australia will lead to the discovery of many new and interesting objects, is proved by the recent acquisition of the lovely species here represented, which was killed by Mr. Gilbert in the newly-located district to the northward of the Darling Downs in New South Wales. In beauty it even exceeds the Rose-Hill Parrakeet, and is consequently one of the finest species of the genus yet discovered. It differs from that bird in having the centre of the breast only of a rich scarlet, the sides being gamboge-yellow; in the lower part of the abdomen and the upper tail-coverts being verditer instead of grass-green, and in the feathers of the back being broadly margined with rich gamboge instead of greenish yellow. In the youthful state it very much resembles the _P. palliceps_, from which however it differs in having the head yellow instead of pale yellowish white, and the breast yellow instead of pale blue; the breast also has indications of the rich scarlet of maturity, of which no trace is at any time perceptible in the _P. palliceps_. Head, sides of the neck and centre of the breast scarlet; cheeks white, faintly tinged with blue; feathers of the back and scapularies black, broadly margined with gamboge-yellow; lower part of the back and upper tail-coverts pale green; on the shoulder a patch of black; wing-coverts pale blue; primaries black with the exception of the basal portion of the external web, which is rich deep blue; two central tail-feathers dark green at the base, passing into deep blue on the apical half of the external web and tipped with black; the next on each side is black on the internal web, green at the base of the external web, blue for the remainder of its length, and slightly tipped with white; the remainder of the tail-feathers are deep blue at the base of the external, and black at the base of the internal web, the remaining portion of both webs being pale delicate blue, passing into white at the tip; sides of the breast and the abdomen bright gamboge-yellow; vent pale green in some, in others pale bluish green; under tail-coverts scarlet; irides dark brown; bill horn-colour; feet mealy brown. The figures are of the natural size, one representing the plumage of youth, the other that of maturity. [Illustration: PLATYCERCUS ICTEROTIS. _J. Gould and H.C. Richter del et lith._ _Hullmandel & Walton Imp._ ] PLATYCERCUS ICTEROTIS, _Wagl._ The Earl of Derby’s Parrakeet. _Psittacus icterotis_, Temm. in Linn. Trans., vol. xiii. p. 120.—Kuhl, Consp. Psitt. in Nova Acta, etc., p. 54. no. 86. _Platycercus Stanleyii_, Vig. in Zool. Journ. 1830, p. 274. —— _icterotis_, Wagl. Mon. Psitt. in Abhand. etc., p. 530.—Gould in Syn. Birds of Australia. _Platycercus icterodes_, Bourj. St. Hil. Supp. to Le Vaill. Hist. Nat. des Perr., pl. 30. _Gȍotd-un-gȍotd-un_, Aborigines of the lowland, and