and Festa, Boll. Mus. Zool., etc., xv, no. 362, 1899, 27 (Vinces and Foreste del Rio Peripa, w. Ecuadór); no. 399, 7 (Laguna del Pita, Panamá). — Thayer and Bangs, Bull. Mus. Comp. Zool., xlvi, 1906, 216 (Sabana de Panamá).
- [Thamnophilus] atrinucha Sharpe, Hand-list, iii, 1901, 14.
- [Thamnophilus] nævius atrinucha Hellmayr, Abh. K. B. Akad. Wias., ii. Kl., xxii Bd., iii. Abth., 1905, 659 (crit.).
- Thamnophilus nævius atrinucha Carriker, Ann. Carnegie Mus., vi, 1910, 602 (Caribbean lowlands and foothills, Costa Rica; crit.; habits; descr. nest and eggs).
ERIONOTUS PUNCTATUS GORGONÆ (Thayer and Bangs).
GORGONA ISLAND ANTSHRIKE.
Similar to E. p. atrinucha but adult male with forehead more extensively grayish,[1] the adult female with lateral under parts paler (nearly concolor with median portion).
Gorgona Island, Bay of Panamá.
Adult male. — Length (skins), 143-148 (146); wing, 70-75 (72.1); tail, 57-61 (59); culmen, 18.5-20 (19.4); tarsus, 20-21 (20.5); middle toe, 12.5-13 (12.7).[2]
Adult female. — Length (skins), 140-148 (144); wing, 68.5-72.5 (70.1); tail, 54.5-57.5 (56.1); culmen, 18.5-20 (19.1); tarsus, 21-21.5 (21.1); middle toe, 13-14 (13.4).[2]
- Thamnophilus gorgonæ Thayer and Bangs, Bull. Mus. Comp. Zool., xlvi, no. 5, June, 1905, 95 (Gorgona Island, Bay of Panamá; coll. E. A. and O. Bangs).
Genus DYSITHAMNUS Cabanis.
- Dysithamnus[3] Cabanis, in Wiegmann's Archiv für Naturg., xiii, pt. i, 1847, 223. (Type, Lanius guttulatus Lichtenstein.)
- Dasythamnus (emendation) Burmeister, Syst. Ueb. Th. Bras., iii, 1856, 82.
- Silvestrius[4] Bertoni, Aves Nuevas del Paraguay, 1901, 136. (Type, Thamnophilus {Silvestrius) flavescens Bertoni = Myothexa mentalis Temminck.)
Small Formicariidæ (length about 100-115 mm.) with bill much shorter than head, tail less than three-fourths as long as wing and slightly rounded, tarsus one-third as long as wing, and plainly colored plumage (olive or olive-greenish above, becoming gray or slate colored on head and neck, the pileum sometimes streaked or spotted with blackish, mostly whitish or yellowish below, sometimes with streaks on throat and chest, females more brownish, with pileum rufescent.
Bill much shorter than head, its width at frontal antiæ slightly greater than its depth at same point and equal to about half the distance from nostril to tip of maxilla; culmnen distinctly but not sharply ridged, nearly straight for most of its length, strongly and rather abruptly decurved terminally, the tip of maxilla moderately
