given rise to the belief that a seasonal change takes place in the
adult.
The young birds of both sexes resemble the adult female up to the first autumn moult. The males then commence to assume the colours of the adult and the change is effected very slowly and probably extends over a whole year.
The Indian Sun-birds may be conveniently divided into two subfamilies.
Sexes different ; plumage of male in part metallic ; bill slender ; nest pensile. Nectariniince, p. 345. Sexes alike ; plumage non-metallic ; bill large ; nest cup-shaped, attached by a portion of the rim to a broad leaf Arachnotherince, p. 368.
Subfamily NECTARINIINCE.
The Sun-birds of this subfamily are characterized by a slender body and an attenuated bill ; by the sexes being different, and by the males having bright metallic colours in their plumage, the females being of a dull green or yellow colour.
Key to the Genera.
a. Covering-membrane of nostril feathered. CHALCOSTETHA, p. 345. b. Covering-membrane of nostril bare. a'. Lower mandible of bill distinctly curved downwards. a". Males with middle tail-feathers elongated ; rump yellow ; females with lower plumage green ^ETHOPYGA, p. 346. b' 1 . Both sexes with short, rounded tails ; females yellow beneath . . ARACHNECHTHRA, p. 357. b'. Lower mandible of bill straight or nearly so ANTHOTHREPTES, p. 3(>">. Genus CHALCOSTETHA, Cabanis, 1850. The genus Chalcostetha contains a single species of Sun-bird, which may be recognized by the covering-membrane of the nostril being completely plumed and by the tail being of considerable length and well graduated. The bill is slender and the lower mandible is nearly straight.
881. Chalcostetha pectoralis. Mnklot's Sun-in,-'!.
Nectarinia pectoralis, Temm. PI. Col. pi. 138, fig. 3 (1823). Nectarinia insignia. Jard. Naturalist's Libr.. Sun-bird*, p. 274 (1848).
Nectarinia insignis, Gould, P. Z. S. 1865, p. 663. Chalcostetha insignis (Jard.), Wuldcn, Ibis, 1870, p. 44; Hume, S.F.
