Auk 



422 Chapman, The Genus Scytalopus Gould. [oct 



Specimens examined. — Costa Rica: Irazu, 6; Panama: Boquete, 

 4; Mt. Chiriqui, 2. 



Key to Adults of the Species of Scytalopus Found North of the 



Equator. 



1. Plumage uniform. 



a. Blackish, not perceptibly paler below than above S. niger. 



b. Grayish, perceptibly paler below than above S. canus. 



2. Plumage not uniform. 



A. Flanks tawny, barred. 



a. A silvery or white superciliary. 



a. 1 Superciliary and forehead silvery S. argentifrons, d 1 . 



a. 2 Superciliary white, forehead blackish like the crown. 



S. panamensis. 



b. Without a superciliary. 

 b. 1 Back gray. 



b. 2 Size small, wing under 55 mm S. sanctce-martce. 



c. 2 Size larger; wing over 58 mm. 



c. 3 Underparts dark slaty, flanks sharply and distinctly barred; 



bill not deeper than wide at base S. m. micropterus. 



c. 4 Underparts mouse-gray, flanks not sharply and distinctly 

 barred; bill much deeper than wide at base. .S. latebricola. 

 c. 1 Back brown. 



c. 2 Forehead neutral gray, tail olive-brownish S. sylvestris. 



d. 2 Forehead and tail blackish. 



d. 3 Wing over 55 mm S. micropterus, 9 . 



d. 4 Wing under 55 mm S. argentifrons, 9 ■ 



B. Flanks tawny, unbarred. 



a. Paler, underparts light neutral gray S. griseicollis . 



b. Darker, underparts deep neutral gray S. infasciatus. 



Synopsis of the Characters of the Juvenal Plumage in Certain 



Species. 



A. Upperparts as well as underparts barred with ochraceous-tawny. 



S. griseicollis, S. sylvestris, S. canus. 



B. Upperparts dark mummy-brown narrowly margined, more rarely 

 inconspicuously barred, with black; underparts widely margined with 

 ochraceous-tawny or cinnamon-buff. 



S. micropterus, S. sancta-martce, S. argentifrons. 



C. Plumage practically unbarred, or bars inconspicuous and restricted 

 largely to flanks and upper-tail coverts, the underparts broadly mar- 

 gined with cinnamon-buff S. niger. 



