Green-tailed Hermit (Phaëthornis viridicaudata), John Gould It would appear that some of the smaller members of the genus Phaëthornis have the lower part of the back and upper tail-coverts buff, while in others those parts are uniform with the upper surface; it is the latter style of colouring which prevails in the bird here figured. 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."