186 VISCOUNT WALDEN ON THE BIKDS 



are but barely fringed with yellow. lu 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 

 0. melanoce])halus 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 0. galbula ; or, 

 in other words, 0. galhula is the older species, B. acrorhynchus and its allies being sub- 

 sequent forms, and 0. melanocephahis and its allies the most recent '. A third species, 

 allied to B. acrorliynclms and B. frontalis, exists in Oriolus formosus, Cabanis, J. f. O. 

 1872, p. 392, "Island of Siou," the largest of all known Orioles. 



Oeiolus, Linnaeus. 



91. * OeIOLTJS PHILIPPENSIS. 

 Oriolus philippensis, J. E. Gray, Zool. Misc. 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 imdoubted Phihppine species (Melanojntta sordida). 



MERULID^. 



TuEDUS, Linnaeus. 



92. TuEDUS OBSCUEUS. 



Dark Thrush, Lath. Synop. ii. p. 31, no. 24, " Siberia, woods beyond Lake Baikal." 



Turdus obscurus, Gm. S. N. i. p. 816, no. 48 (1788), ex Lath.; Bp. Compt. Rend, xxxviii. p. 4; 



Coll. Delattre, p. 28. 

 Turdus riifulus, Drapiez, Diet. Class. d'Hist. Nat. x. p. 443, "Java" (1826). 

 Turdus paUens, Pallas, Zoographia Rosso- Asiatica, i. p. 457, no. 98, "Dauria" (1831) ; Temm. & 



Schlegel, Faun. Japou. Aves, p. 63, pi. 27. 

 Turdus iliacus pallidus, Naumanu. 

 Turdus seyffertitzii, Brelim, Vog. Deutschlands, p. 387, " Herzbiu-g, in Saxony " (1831). 



' This generalization is not grounded on the phenomena presented hy tlie Orioles alone. It is impossible not 

 to be struck hy 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. Swiuh. Ibis, 1803, p. 292. 



