ACANTHOPNEUSTE. 585 
mingled with yellowish; under plumage white, suffused with yellow; 
under wing-coverts and axillars pale yellow. 
“As the summer goes on the wing-bars get worn away and the upper 
one is sometimes absent. The lower plumage gets whiter and the upper 
plumage duller. After the autumn molt the wing-bars are very con- 
spicuous and the under parts become suffused with deeper yellow. 
“Upper mandible dark brown, the edges and tip yellow; gape and 
basal half of the lower mandible orange-yellow, terminal half dusky; 
mouth bright orange-yellow; iris dark brown; legs flesh-color tinged 
with yellow; claws yellowish horn-color. Length, 122; tail, 51; wing, 
68.5; tarsus, 20; bill from gape, 17; the second primary is interme- 
diate in length between the fifth and sixth, and is sometimes equal to 
the sixth; the first primary is very small, measuring from 7.6 to 11.4 
in length.” (Oates.) 
The arctic willow warbler is the commonest species of the genus and 
is found in the Philippines during the winter months. Most of the 
specimens taken at this time have the under parts but faintly suffused 
with yellow and in this plumage the wing-bar is indicated by light spots 
on the outer webs of some of the greater coverts. This plainly colored 
species is usually seen flitting among the branches of forest trees and 
at such heights that it can not be distinguished from other species of 
similar habits. 
569. ACANTHOPNEUSTE XANTHODRYAS (Swinhoe). 
YELLOW WILLOW WARBLER, 
Phylloscopus xanthodryas SwinuHok, Proc. Zool. Soe. (1863), 296; Sersoum, 
Cat. Birds Brit. Mus. (188]), 5, 42. 
Acanthopneuste xanthodryas SHARPE, Hand-List (1903), 4, 217; McGrercor 
and WorcrsTER, Hand-List (1906), 90. 
Apo (Celestino) ; Basilan (McGregor) ; Cagayancillo (McGregor) ; Cebu (Me- 
Gregor) ; Luzon (Celestino) ; Mindanao (Celestino) ; Palawan (Hverett). Mon- 
golia, Japan, Kamtchatka, and the Kurile Islands; in winter to southern China 
and Borneo. 
“Spring plumage.—General color of the upper parts olive, slightly 
yellower on the rump; eye-stripe well defined, narrow, yellowish white, 
extending to the nape; lores and the feathers behind the eye to the 
nape dark olive; wing-coverts olive, the median wing-coverts with narrow, 
and the greater wing-coverts with broad yellowish white tips, forming 
an obscure upper wing-bar and a conspicuous lower wing-bar; quills 
brown, narrowly tipped with grayish white, the outside web edged with 
green and emarginated as in the preceding species ; tail-feathers brown, the 
outside web margined with green, and the inside web with a narrow 
well defined grayish white margin; general color of the under parts 
greenish yellow, grayer on the breast and flanks; axillars, under wing- 
coverts, and thighs pale yellow; inner margin of quills grayish white. 
