620 Annals of the Carnegie Museum. 



C. H. Lankester Collection : Miravalles, La Florida, Guacimo. 

 Carnegie Museum : Guapiles and Guacimo (Carriker & Crawford) ; 



Guacimo, Cuabre, Rio Sicsola, Guapiles, Carrillo, Miravalles, 



Bagaces (Carriker). Twenty-two skins. 



Mr. Bangs has separated the birds of this species from Costa Rica 

 and Chiriqui from those from Panama and southward, but after a care- 

 ful examination of a large series I have concluded that the differences 

 are altogether too slight to justify such a separation. Costa Rican 

 birds have the back darker and richer chestnut and the black spotting 

 on the breast a trifle heavier, otherwise they are exactly the same as 

 specimens from Panama. 



This is a very common bird over the whole of the Caribbean low- 

 lands from sea-level up to about 2,000 feet, and is the most abundant 

 ant-thrush in northwestern Costa Rica, especially in the Guanacaste 

 region. It is usually found in fairly heavy forest, and is almost en- 

 tirely arboreal in its habits, hopping and climbing about among the 

 undergrowth, shrubbery, and low limbs of the trees. It is a very 

 noisy little bird and usually goes about in small bands in company with 

 some of the other arboreal ant-thrushes and tree-creepers {Dendro- 



colaptidce.) 



I found a nest of this species at Guacimo in April, 1903, containing 

 two young birds. It was a roughly built structure of leaves, rootlets, 

 and weed-fiber, of the ordinary shape (like Myrmeciza exsul) and 

 placed in a low bush in the heavy forest, just beside a path. 



355. Gymnocichla nudiceps erratilis Bangs. 



Myiothera nudiceps Cassin, Proc. Acad. Nat. Sci. Phila., V, 1850, 106, pi. 6 

 (Panama [J. G. Bell; coll. Phil. Acad. Sci.]). 



Gymnocichla nudiceps Sclater, P. Z. S., 274; Cat. Birds Brit. Mus., XV, 1890, 

 272, part (no C. R. record). — Salvin and Godman, Biol. Centr.-Am., Aves, 

 II, 1892, 223, part (no C. R. record). — Cherrie, Expl. Zool. en C. R., 

 1890-1, 1893, 42 (Boruca, Terraba, and Buenos Aires; first record for Costa 

 Rica). 



Gymnocichla nudiceps erratilis Bangs, Auk, XXIV, 1907, 297 (cotypes from 

 Boruca [Underwood]; other specimens from El Pozo de Terraba). 



U. S. Nat. Museum : Pigres (Ridgway and Zeledon). 



Bangs Collection : El General and Buenos Aires de Terraba (Under- 

 wood). 



Carnegie Museum : Boruca and Paso Real (Carriker). Four skins. 

 The type of G. nudiceps is from Panama, where the birds (espe- 



