“Its powers of flight are considerable, and when excited during the breeding-season the males become very pugnacious, and not only attack each other in the most desperate manner, but also assault much larger birds that may approach the nest. Its usual flight is even, steady and graceful, and while flying from tree to tree it gives utterance to its sweet and agreeable song, which at times is so like the full, swelling, shaking note of the Canary, that it might easily be mistaken for the song of that bird. It is a remarkably shy bird, especially the females, which are so seldom seen that I was at first inclined to think they were much less numerous than the other sex, but this I afterwards found was not the case; their favourite haunts are thickly wooded places and the most secluded spots. The nest is so diminutive that it is very difficult to detect it, and so shallow in form that it is quite surprising the eggs do not roll out when the branch is shaken by the wind. I am told that they generally build in the Raspberry-Jam-tree, but the nests I discovered were placed on a horizontal dead branch of a Eucalyptus; they were formed of grasses and contained two eggs. It breeds in the latter part of September and the beginning of October.” Mr. Gilbert subsequently met with the bird at Port Essington, where also it appears to be migratory, for not a single individual was to be seen from the early part of November to the month of March; females and young birds were very abundant on his arrival in July, but he only met with one old male during his residence in the colony, a period of eight months. The stomach is muscular, and the food consists of insects of various kinds and their larvæ. The sexes differ considerably in colour, as will be seen in the accompanying Plate and the following description:— The male has the forehead, crown of the head, back of the neck and upper part of the back glossy greenish black; shoulders and upper wing-coverts pure white, forming an oblique line along the wing; the remainder of the wing dull black, with the secondaries slightly margined and tipped with white; lower part of the back and rump grey; tail dull black, the two outer feathers on each side largely tipped with white; throat, chest and all the under surface white; bill and feet black; irides nearly black. The female has all the upper surface, wings and tail brown; wing-coverts and secondaries margined with buff; throat and all the under surface buffy white, with the sides and front of the breast speckled with brown; irides very dark brown; upper mandible and tip of the lower dark reddish brown; basal portion of the latter saffron-yellow; legs and feet dark greyish black, slightly tinged with lead-colour. The figures represent the two sexes of the size of life. [Illustration: PACHYCEPHALA GUTTURALIS. _J. Gould and H. C. Richter del et lith._ _Hullmandel & Walton Imp._ ]