Mr. Gilbert killed several specimens of this little bird on the Cobourg Peninsula, and on the islands in Van Diemen’s Gulf, and sometimes observed a solitary individual among the mangroves near the settlement of Port Essington. He states that it has a very pleasing but weak piping note, and occasionally utters a number of notes in slow succession, but not so much lengthened as those of the _Gerygone culicivorus_ of Swan River; like that bird it hovers up and down the smaller branches of the trees and creeps about the thickets. It is very tame, and scarcely ever flies from the tree upon the approach of an intruder, but sits turning its little head about from side to side until the hand is almost upon it, when it merely hops upon another branch and again quietly looks about, apparently quite unconcerned. The stomach is tolerably muscular, and the food consists of small insects, principally of the soft-winged kinds. A narrow obscure line, commencing at the nostrils and passing over the eye, yellowish white; all the upper surface rusty brown; primaries brown, margined with lighter brown; tail whitish at the base, gradually deepening into nearly black, the lateral feather largely, and the remainder, except the two middle ones, slightly tipped with white; all the under surface white, slightly washed with yellow; irides light reddish brown; bill olive-brown; base of lower mandible light ash-grey; feet dark greenish grey. The figures represent the two sexes of the natural size. [Illustration: GERYGONE CHLORONOTUS: _Gould_. _J. Gould and H. C. Richter del et lith._ _Hullmandel & Walton Imp._ ] GERYGONE CHLORONOTUS, _Gould_. Green-backed Gerygone. _Gerygone chloronotus_, Gould in Proc. of Zool. Soc., Part X. p. 133. This species is an inhabitant of the northern parts of Australia: it is tolerably abundant at Port Essington, where it dwells among the extensive beds of mangroves which stretch along the coast. It is of a very shy and retiring disposition, and as the colouring of its back assimilates very closely to that of the leaves of the mangroves, it is a very difficult bird to sight as it creeps about among the thick branches in search of insects, upon which it solely subsists. In form and in most of its habits and economy it offers some difference from the typical members of the genus _Gerygone_, and it would be no great stretch of propriety to assign to it a new generic appellation: the more lengthened form of its legs, the more rigid structure of its primaries, and the lesser development of the bristles at the gape, are among the points in which it differs from the _Gerygone fuscus_ of the brushes of New South Wales. The latter feeds upon the smallest kinds of gnats and other soft insects which it captures in the air; on the other hand, the structure of the present bird would lead us to infer that the insects it feeds upon are procured either on the leaves or about the branches.