This is the gem of Jamaican Ornithology. Its slender form, velvet crest, emerald bosom, and lengthened tail-plumes, render it one of the most elegant even of this most brilliant family. Though peculiar, as far as I am aware, to Jamaica, it has long been known, though it would seem from received figures and descriptions very imperfectly. Edwards long ago gave a figure of it, which is recognisable. Lesson’s figure and description are alike bad. The attitude is that never assumed by a Humming-bird; the back of the neck is made green instead of black; the scaly emerald plumage is diminished to a mere gorget instead of extending over the whole breast and belly; the beak and feet are both made yellow, whereas the former should have been crimson, the latter purple-black. He makes “Les Polythmus” his tenth Race, which he thus defines: “Beak short, straight: the external tail-feathers terminated by two long blades or filaments (_brins_).” Here every character is incorrect. The beak, though not long, is certainly not short; it is not straight, but perceptibly curved, particularly in the female; the curvature, it is true, varies in individuals, but I possess several females whose beaks are more curved than that of Mango; it is not the external tail-feather that is lengthened, but the second from the outside; lastly, this feather is not terminated by a filament, or by any structure varying from the other part; it is simply produced in length. Mr. Swainson writes as if he were unacquainted with this species, for in speaking of the tendency of the lengthened external feathers of the tail in certain families of birds to turn _outwards_ towards their tips, he observes, “there is one solitary instance where these long exterior feathers are turned _inwards_ instead of outwards: this occurs in a Humming-bird figured by Edwards, as a native of Jamaica, _but we have never yet_ seen it, nor is a specimen known to exist at this time in any museum.” (Class. Birds, I. 105.) This is no other than Polytmus; the long tail-feathers of which do bend inwards so as to cross each other when the bird is resting. I may add here that these long feathers have the inner edge prettily waved, not by actual indentation, but by a puckering of the margin, like a frill.