White-tailed Emerald (Thaumatias chionurus), John Gould I have before had occasion to remark how different are the species inhabiting Mexico, or the country to the northward of the Isthmus of Panama, from those of the southern portions of the continent of South America, and the present species may be cited as a striking instance in point; for while it is of precisely the same form as its near allies, the well-known Thaumatias albirostris and T. brevirostris of Brazil, in colouring it is very different from both of those birds; in fact it may be said to differ from every other known species of Humming-Bird, from the great amount of white which pervades the under surface and the tail-feathers. This illustration has been restored to its original vibrancy by enhancing colors and removing unwanted marks. A monograph of the Trochilidæ, or family of humming-birds was published between 1849 and 1887 by English ornithologist John Gould. This monumental work depicts and describes all the known species of hummingbirds at the time - comprising 418 lithographic plates and information on 537 species."