The _Cysticola lineocapilla_ is a much smaller and more delicately formed species than the _C. exilis_, and may, moreover, be distinguished from that and every other member of the genus with which I am acquainted by the lineated form of the markings of the head. It is a native of the north coast of Australia, and all the specimens I have seen were from the neighbourhood of Port Essington. Mr. Gilbert states that it “is very rarely seen in consequence of its generally inhabiting the long grass of the swamps, where it creeps about more like a mouse than a bird, and if once alarmed it is no easy task to get a sight of it again; its note is a short and feeble, but very pleasing song. “The stomach is muscular, and the food consists of insects of various kinds.” General plumage pale rufous, with broad and conspicuous striæ of blackish brown forming lines down the centre of the feathers of the head and back; the under surface fading into white on the throat and centre of the chest; tail-feathers with a conspicuous blackish spot on the under surface near the tip; irides light reddish brown; bill and feet flesh-brown. The figures are of the natural size. [Illustration: CYSTICOLA ISURA: _Gould_. _J. Gould and H. C. Richter del et lith._ _Hullmandel & Walton Imp._ ] CYSTICOLA ISURA, _Gould_. Square-tailed Warbler. _Cysticola isura_, Gould in Proc. of Zool. Soc., Part XV. Little as is the information I have been able to give respecting the _C. ruficeps_, I have still less to communicate about the present species, circumstances not having admitted of my seeing them in a state of nature: at a first glance it might readily be mistaken for the _C. exilis_, but after a careful examination of many specimens I am satisfied of its being distinct; had it been identical with that species, I must have procured specimens at the same time that I killed the many examples I obtained. I am not so sure however that it may not prove to be the female, or some peculiar state of plumage of the _Cysticola ruficeps_; without a further knowledge of the subject, I can only view it as distinct from both, and I have therefore assigned to it the specific appellation of _isura_, as indicative of the shorter and more truncated form of its tail, the principal character by which it may be distinguished. Like the other species of the group, it appears to enjoy an extensive range over the grassy districts of the country, the specimens in my possession having been killed on the Liverpool Plains and at Port Phillip; the arid and sterile nature of the country seems to be peculiarly adapted to the members of this group, and hence there are many species.