186 VISCOUNT WALDEN ON THE BIRDS 
are but barely fringed with yellow. In a Luzon male in similar dress the two middle 
rectrices have a yellow terminal band nearly half an inch in depth. 
The tendency in this species seems to be for the entire head to become black as in 
O. melanocephalus and its allies. In an immature Luzon male (fide Meyer), with dingy 
greenish-yellow plumage and streaked breast, the feathers of the nape, occiput, and lores 
are dingy greenish yellow with greenish black, those of the. forehead being dingy 
golden. Now in the adult these nuchal, occipital, and loral feathers become jet-black 
at their tips, those on the neck being ashy or greenish ash at their roots, but those on 
the occiput being bright yellow at their insertions. The direction of variation in this 
species may therefore be said to be towards 0. melanocephalus, and from O. galbula; or, 
in other words, O. galbula is the older species, B. acrorhynchus and its allies being sub- 
sequent forms, and 0. melanocephalus and its allies the most recent’. A third species, 
allied to B. acrorhynchus and B. frontalis, exists in Oriolus formosus, Cabanis, J. f. O. 
1872, p. 392, “Island of Siou,” the largest of all known Orioles. 
OrtoLvs, Linneus. 
91. * ORIOLUS PHILIPPENSIS. 
Oriolus philippensis, J.B. Gray, Zool. Mise. p. 3, “ Philippine Islands ” (1831); Bp. Consp. i. p. 346. 
Stated by its describer to have been discovered by Captain Hay in the Philippine 
Islands. It is not represented in the British Museum, and does not appear to have 
been again obtained. The type specimen was without feet or wings, and was procured 
from the natives. Its origin might be considered more than doubtful, were it not that 
it was procured along with an undoubted Philippine species (MJelanopitta sordida). 
MERULID. 
Turpvus, Linnzus. 
92. TuRDUS OBSCURUS. 
Dark Thrush, Lath. Synop. ii. p. 31, no. 24, “ Siberia, woods beyond Lake Baikal.” 
Turdus obscurus, Gm. 8. N. i. p. 816, no. 48 (1788), ex Lath.; Bp. Compt. Rend. xxxviii. p. 4; 
Coll. Delattre, p. 28. 
Turdus rufulus, Drapiez, Dict. Class. d’Hist. Nat. x. p. 443, “ Java” (1826). 
Turdus pallens, Pallas, Zoographia Rosso-Asiatica, i. p. 457, no. 98, “ Dauria” (1831); Temm. & 
Schlegel, Faun. Japon. Aves, p. 63, pl. 27. 
Turdus iliacus pallidus, Naumann. 
Turdus seyffertitzi, Brehm, Vog. Deutschlands, p. 387, “ Herzburg, in Saxony ” (1831). 
* This generalization is not grounded on the phenomena presented by the Orioles alone. It is impossible not 
to be struck by the numberless proofs the study of birds affords of the tendency of one species to develop into 
another. On the phases of plumage in B. sinensis, conf. Swinh. Ibis, 1863, p. 292. 
