Page:Birds of North and Middle America partV Ridgway.djvu/123

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BIRDS OF NORTH AND MIDDLE AMERICA.

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Peripa, w. Ecuadór; crit.). — Salvin and Godman, Biol. Centr.-Am., Aves, ii, 1892, 214, part (Lion Hill, Panamá, and Chepo, Panamá; Colombia; Ecuadór; Peru; Guiana). — Bangs, Proc. New Engl. Zool. Club, ii, 1900, 23 (Loma del Leon, Panamá). — Hartert, Novit. Zool., ix, 1902, 612 (San Javier and Pambilár, n. w. Ecuadór; crit.). — Berlepsch and Hartert, Novit. Zool., ix, 1902, 76 (Munduapo, etc., Venezuela). — Hellmayr, Novit. Zool., xii, 1905, 286 (near Pará, Brazil; crit.); xiii, 1906, 370 (Prata, near Pará); xiv, 1907, 32 (Obidos, Brazil; crit.). — Thayer and Bangs, Bull. Mus. Comp. Zool., xlvi, 1906, 217 (Sabana de Panamá).

[Cercomacra] tyrannina Pelzeln, Orn. Bras., iv, Abth., 1870, 419. — Sclater and Salvin, Nom. Av. Neotr., 1873, 73, part. — Sharpe, Hand-list, iii, 1901, 28, part (Panama; Colombia; Ecuador; Guiana; Amazonia).

Hypocnemis schistacea (not of Sclater) Lawrence, Ann. Lyc. N. Y., vii, 1862, 325 (Lion Hill, Panamá).

Disythamnus rufiventris Lawrence, Ann. Lyc. Nat. Hist. N. Y., viii, 1867, 131 (Lion Hill, Panamá; coll. G. N. Lawrence; = young male; see Salvin, Ibis, 1874, 316).

CERCOMACRA TYRANNINA CREPERA (Bangs).

DUSKY TYRANNINE ANTBIRD.

Similar to C. t. tyrannina but adult male with coloration averaging much darker, the general color of upper parts blackish slate to slate- black, under parts slate color to blackish slate; adult female and young male not always distinguishable from those of C. t. tyrannina, but usually with color of upper parts darker and more brownish olive, the under parts decidedly deeper tawny.^[1]

Adult male. — Length, (skins), 124-148 (137); wing, 60-67 (63.4); tail, 54.5-62.5 (57.2); culmen, 15-18 (16.6); tarsus, 21.5-24 (22.9); middle toe, 12.5-14 (13.5).^[2]

↑ There is much variation in intensity of coloration among specimens from Costa Rica and northward. As a rule, specimens from the Caribbean slope are much darker than those from the Pacific side, and were the differences strictly geographical two well-marked forms could easily be made out; but unfortunately both slate-colored and blackish examples sometimes occur in the same locality, as in eastern Nicaragua (Rio Escondido), Honduras (Rio Blanco and San Pedro Sula), while extreme dark specimens come from Bebedero, northwestern Costa Rica, and light colored ones from British Honduras. A large majority of the specimens from southwestern Costa Rica are so light colored that they could almost be referred to true C. tyrannina; but much darker ones occasionally occur there also. Specimens from Venezuela agree exactly with those from Bogotá and Panamá; but two adult males from Reyes and Mapiri, Bolivia, respectively, are quite as dark as the darkest examples of C. t. crepera. On the whole, I consider our present understanding of this species, with reference to its geographic variations, far from satisfactory.
↑ Forty-four specimens.

[1] There is much variation in intensity of coloration among specimens from Costa Rica and northward. As a rule, specimens from the Caribbean slope are much darker than those from the Pacific side, and were the differences strictly geographical two well-marked forms could easily be made out; but unfortunately both slate-colored and blackish examples sometimes occur in the same locality, as in eastern Nicaragua (Rio Escondido), Honduras (Rio Blanco and San Pedro Sula), while extreme dark specimens come from Bebedero, northwestern Costa Rica, and light colored ones from British Honduras. A large majority of the specimens from southwestern Costa Rica are so light colored that they could almost be referred to true C. tyrannina; but much darker ones occasionally occur there also. Specimens from Venezuela agree exactly with those from Bogotá and Panamá; but two adult males from Reyes and Mapiri, Bolivia, respectively, are quite as dark as the darkest examples of C. t. crepera. On the whole, I consider our present understanding of this species, with reference to its geographic variations, far from satisfactory.

[2] Forty-four specimens.

[1]

[2]