Tribura Hodgs., P. Z. S., 1845, p. 30. Type, T. luteoventris.
The genus Tribura contains four species, all of which breed in the mountains, only visiting the plains of India and Burma in the cold weather.
These "Warblers are birds of plain plumage and the feathers are very soft and silky in their texture. The sexes are alike but the young differ from the adults in being much more yellow. The second or Spring moult is complete or nearly so.
The four Indian species of Tribura are not perfectly congeneric, one differing from the others in its extremely large bill- whilst a second species is distinguished from the other three by the shape of the wing. These differences are, however, paralleled in the genus Acrocephalus, to which Tribura is very closely allied and do not seem to necessitate any further division of genera.
In T. major the bill is nearly as long as the head, in the other species about half the length of the head ; in all four it is slender and straight. The rictal bristles are minute and invisible without a lens ; the forehead is smooth and free from all hairs etc; the wing is fairly long; the tail much rounded and the feathers rather pointed ; the tarsus is rather long, though slight. *
Key to Species.
A. First primary much less than half the second.
a. Bill at front 15 mm. or over T. major, p. 403.
b. Bill at front 13 mm. or under……………….T. taczanowskia, p. 404.
B. First primary about half the length of the second
c. Throat ashy, spotted with black T. thoracica, p. 405.
d. Throat unspotted white T, luteoventris, p. 406.