450 BRITISH BIRDS. : 
bars, and nearly all from the underparts, leaving the colour greyish white ; 
the conspicuous pale tips to the secondaries and some of the primaries 
have generally entirely disappeared ; the lower wing-bar and the pale edges 
to the innermost secondaries have become very narrow; and traces only 
of the upper wing-bar are left. The autumn plumage is similar to that 
of spring, but more brilliant, the eye-stripes and the wing-bars yellower, 
and the upper parts a yellower green; the mesial line on the crown remains 
as obscure, and the underparts scarcely yellower. In winter the same 
amount of abrasion takes place as in summer; but the upper parts do not 
become so grey, and the eye-stripe and wing-bars retain a trace of yellow. 
The Yellow-browed Warbler has several near allies. Two of these, which 
breed in the Himalayas, P. erochroa and P. maculipennis, may be at once 
distinguished by having the inner web of the two outside tail-feathers on 
each side pure white. A third, P. proregulus, breeding in the Himalayas 
and in the subalpine districts of South-eastern Siberia, differs from its 
northern representative in having a bright yellowrump. ‘Two other species, 
P. subviridis and P. humii, also breeding in the Himalayas, but ranging 
westwards, the one into Gilgit, north of Cashmere, and the other into 
Turkestan, are more difficult to discriminate. They may generally be told 
by their wing-formula, the second primary being usually intermediate in 
length between the eighth and the ninth, whilst in the Yellow-browed 
Warbler it is usually between the sixth and seventh. resh-moulted 
examples of P. humii may be discriminated by their buff eye-stripe, of 
P. subviridis by the much yellower green of its upper and the greener tint 
of its underparts, and of both by their obscure upper wing-bar. 
