ELANUS HYPOLEUCUS, Gowa. Celebean Elanus. Elanus hypoleucus, Gould in Proc. of Zool. Soc., part xxv. p. 127. Tuere is not a more distinct and better-defined group of Hawks than those forming the genus E/anus, the members of which are widely spread over both the Old and the New World. In America the Elanus leucurus has a wide range, from Mexico to Brazil; Africa, India, and the Indian Islands are inhabited by three others; one, the Z. melanopterus, ranges over Southern Europe, the whole of Africa, and India ; Australia, however, appears to be the head-quarters of the genus, two species at least, the E. axillaris and £. scriptus, inhabiting that country. The present bird differs from all the other members of the genus; it is most nearly allied to £. axillaris, but exceeds that bird in size, and is destitute of the black spot on the under surface of the wing. It is true, some small tippings of black are seen, but they occur on a different part to the spot in Z. aaillaris: the character by which it may at all times be distinguished is the silvery-white hue of the under surface of the primaries throughout their whole length. Mr. Wallace sent specimens of both old and young birds from Celebes; I have seen another example in the collection of T. C. Eyton, Esq., which was procured in the Philippines ; and J. H. Gurney, Esq., informs me that he has seen specimens from Java; this latter island, then, appears to be the portion of the Old World where two, if not all the species of the genus inosculate; the E. avillaris is certainly found there, and, if I mistake not, the /. melanopterus also. There seems to be no difference in the colouring of the sexes ; the young, on the other hand, as will be seen on reference to the Plate, are distinguished by having the head striated with reddish brown, and by having a crescent of white at the tips of the wing-feathers. The adult has the face, space over the eye, ear-coverts, and all the under surface of the body, under surface of the wing, under tail-coverts, under surface of the tail-feathers, and the thighs pure white; basal half of the under side of the first six primaries white, slightly speckled with grey, passing into blackish grey; on their apical halves this grey hue also pervades the under surface of the remaining primaries ; crown of the head, back of the neck, back and scapularies deep grey; on the shoulders a large patch of black ; secondaries and basal half of the primaries deep grey, passing into blackish grey at their tips; two centre tail-feathers grey above, the next on each side grey on their outer margins, the rest white; cere and legs orange-yellow ; bill and nails black. The young at apparently about nine months old differ from the adult in having the crown lineated with reddish brown, and a crescent of white at the tip of the primaries, secondaries, scapularies, and wing- coverts. The figure in the Plate is of the size of life.