802 Annals of the Carnegie Museum. 



There can be no question of the identity of the specimens, Mr. Ridgway 

 having examined them and pronounced them to be W. p. pusilla. They 

 were taken in the extreme northwestern portion of the country, on the 

 Pacific slope, and no specimens of W. pusilla pileolata were taken on the 

 trip, from which we may infer that that region is not visited by W. p. 

 pileolata. This is certainly an extraordinary distribution, the eastern 

 form of the bird being taken only on the Pacific slope of Costa Rica, while 

 the western race of the same species occupies the whole of the remainder 

 of the region in great numbers. 



599. Wilsonia pusilla pileolata (Pallas). 



Motacilla pileolata Pallas, Zoogr. Rosso-Asiat., 1826, 497 (Kadiak Island, 



Alaska). 

 Sylvania pusilla pileolata Cherrie, Auk, VII, 1890, 337 (San Jose, Costa Rica, 



Oct. 27 to March 6; most abundant warbler). — Zeledon, An. Mus. Nac. 



de C. R., I, 1887, 107 (Dota, Cartage). 



Myiodioctes pusillus ft. M. pileolatus Sharpe, Cat. Birds Brit. Mus., X, 1885, 

 437 (Barranca [Carmiol], Irazu. district [Rogers]). 



Myiodioctes pusillus Cabanis, Jour, fur Orn., i860, 325 (highlands of Costa 

 Rica, Sept. [Hoffmann and Frantzius]). ■ — Frantzius, Jour, fiir Orn., 1869, 

 294 (plain of San Jose, August; Poas, March). — Boucard, P. Z. S, 1878, 

 52 (San Jose, January).— Lawrence, Ann. Lye. N. Y., IX, 1868, 95 (Barranca 

 and Grecia [J. Carmiol], San Jose [Frantzius]). — Ridgway, Proc. U. S. Nat. 

 Mus., V. 1882, 494 (Volcan de Irazu [Nutting]). — Salvin and Godman, 

 Biol. Centr.-Am., Aves, I, 1881, 168 (Irazu [Rogers]. Orosi [Kramer]). 



Wilsonia pusilla pileolata Coues, Bull. Nutt. Orn. Club, V, 1880, 95, part. — 

 Ridgway, Birds N. and Mid. Amer., II, 1902, 712 (western North America, 

 south in winter over the whole of Mexico and Central America to Cbiriqui). 

 — Bangs, Proc. Biol. Soc. Wash.. XXII, 1909, 36, in text (high elevations 

 in central and southern Costa Rica). 



U. S. Nat. Museum: Volcan de Turrialba (Ridgway and Zeledon), San 



Juan de Irazu, Coliblanco, April and May (Ridgway). 

 Bangs Collection: Volcan de Irazu (Underwood), Dec. 3 to 30. 

 C. H. Lankester Collection: Cachi. 

 Carnegie Museum: Volcan de Irazu, April 7 to 12; Cuabre, March 2; 



Guapiles, Jan. 20; La Hondura, Sept. 22; Juan Vinas, April 19 (Car- 



riker). Nine skins. 



A very common migrant in Costa Rica, covering in abundance the whole 

 of the Caribbean slope down to sea-level and up to timber-line on the high 

 volcanoes. There are no records for either race of W. pusilla in south- 

 western Costa Rica, and only for W. p. pusilla in the northwestern part. 

 The present form is found over the whole region of the central plateau, 

 but evidently does not occupy the lower parts of the Pacific slope. 



