The extreme brilliancy of the plumage of this bird would seem to indicate that it is an inhabitant of a hotter climate than that of New South Wales, and the correctness of this inference is borne out by the fact that the _Halcyon MacLeayii_ has only yet been found on the extreme northern portion of the continent; it is tolerably abundant at Port Essington, and it is also spread over every part of the Cobourg Peninsula suited to its peculiar habits; like the other members of the genus to which it belongs, it is rarely if ever seen near water, and evinces so decided a preference for the open forests of the interior of the country that it has obtained the name of “Bush Kingfisher” from the residents at Port Essington; it is generally dispersed about in pairs, and feeds on small reptiles, insects and their larvæ; its general note is a loud _pee-pee_ uttered with considerable rapidity. It incubates in November and December, sometimes forming its nest in the hollow trunks of trees, and at others excavating a hole for itself in the nest of the tree-ants, which presents so prominent and singular a feature in the scenery of the country: the nest of the _H. Macleayii_ is easily discovered, for on the approach of an intruder the birds immediately commence flying about in a very wild manner, uttering at the same time a loud piercing cry of alarm; the eggs are three or four in number, of a pearly white and nearly round in form, being eleven lines long by ten broad. So much difference exists in the plumage of the sexes that Mr. Gilbert states he was for some time induced to regard them as specifically distinct; an error into which I had myself previously fallen when describing the female as a new species in the “Proceedings of the Zoological Society” as quoted above; “but upon closer observation,” adds Mr. Gilbert, “I soon satisfied myself that the difference of plumage was merely sexual, the dissection of a large number of specimens fully proving that those with a ring round the neck are males and those without it females.” The male has a line under the eye and ear-coverts deep glossy black; head, occiput, wings and tail rich deep prussian blue; primaries and secondaries white at the base, forming a conspicuous spot when the wings are spread; for the remainder of their length these feathers are black, margined externally with light prussian blue; immediately before the eye an oval spot of white; collar surrounding the back of the neck and all the under surface white, tinged with buff on the lower part of the flanks; back and upper tail-coverts verditer blue; scapularies verditer green, both these colours bounded near the white collar with prussian blue; under surface of the wing white, the tips of the coverts black; under surface of the tail black; bill black, the basal portion of the under mandible yellowish white; tarsi black; inner side of the feet and back of the tarsi ash-grey; irides very dark brown.