Hitherto this species has been divided into two so-called species, 0. mollissima and 0. dixoni, the latter being said to differ in having a longer tail and more conspicuously barred wing-coverts. I have shown in the Bulletin of the British Ornithologists' Club, xxxi, p. 81, that these alleged differences are not specific or even subspecific; the two supposed forms are found throughout the same range, i.e. from Chamba m the extreme North-East of India, to the South-East Shan States and Central Burmese Hills, at the same elevation.
A subspecies of this Oreocincla had, however, been overlooked until discovered by Captain C. H. T. "Whitehead on the extreme North-East Afghan-Indian frontier.
Key to Subspecies.
A. Upper parts rich olive-brown, tinged with
rufous O. m. mollissima, p 162.
B. Upper parts olive-grey with no rufous
tinge O. m. whiteheadi, p. 163.
C. Upper parts olive-brown, paler than in A
and with golden tinge O. m. simlaensis, p. 164.