Mr Gould describes the Mars' sun-angel as among the most beautiful of
the genus Heliangelus inhabiting the northern end of the Cordilleras.
"It has all the charms of novelty to recommend it, and it stands alone
among its congeners; no other member of the genus, similarly coloured,
having been discovered up to the present time. The throat vies with the
radiant topaz, while the band on the forehead rivals in brilliancy the
frontlet of every other species. The male bird has a fiery red mark on
its forehead, and the crown of the head and upper surface of the body
are bronzed green. The throat is ornamented with a gorget of deep fiery
red, and below it is a crescent-shaped band of light buff, while the
under part is of a deeper buff, changing to green at the sides. The
tail is of a bronzed brown, with the two centre feathers of bronzed
green. The female is destitute of the red mark on the throat and
forehead."