Heloisa’s Flame-bearer (Selasphorus Heloisæ), John Gould This beautiful species is so directly intermediate, both in form and colouring, between the members of the genera Calothorax and Selasphorus, that it is extremely difficult to determine with which of them it should be placed; in its size and in its glittering gorget it offers a close affinity to the former, and in the form of its tail to the latter; under these circumstances, some naturalists would make it the type of a new genus, and should other species possessing similar characters be discovered, it may be necessary so to do, but for the present I content myself with placing it in the genus Selasphorus, with a mark of doubt as to that being its proper place. 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."