Il8 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



blackish brown; wings and tail heavily barred with black; sides, fore- 

 neck, and upper breast chestnut; rest of undersurface dull grayish 

 brown; undertail coverts in one race chestnut. Rarely, an aberrant in- 

 dividual may have the foreneck and upper breast partly or entirely pure 

 white. 



These widely distributed wrens average slightly larger in body than 

 other forest wrens, and also have heavier bills. Perhaps on account of 

 this slightly stronger form, they seem somewhat more aggressive than 

 related species, and so are seen more easily. They are also more ter- 

 restrial than any other wren besides Microcer cuius. 



The species ranges chiefly in the humid lowlands, along the Carib- 

 bean slopes of southern Honduras, Nicaragua, Costa Rica, and Panama, 

 reaching the Pacific slope in humid hill country of northwestern Costa 

 Rica and of western Province of Panama (Cerro Campana) and locally 

 extending over the Pacific slope in the lowlands of eastern Panama. It 

 is also found in Colombia on both slopes and widely in Amazonia. 

 Populations from Panama northward, western Colombia, and the Pa- 

 cific slope of Ecuador are often separated, as C. phaeocephalus, from 

 the C. aradus group found east of the Andes (Hellmayr, Cat. Birds, 

 Am., pt. 7, 1934, p. 292). 



CYPHORHINUS ARADUS INFUSCATUS Zimmer 



Cyphorhinus lawrencii infuscatus Zimmer, Amer. Mus. Nov., no. 573, Oct. 11, 

 1932, p. 3. (Carrillo, Costa Rica.) 



Characters. — Darker throughout than the race lawrencii, found else- 

 where throughout Panama; dorsal surface blackish brown throughout, 

 with the forecrown in some blacker; chestnut-brown on side of head, 

 foreneck and upper breast distinctly darker; rest of undersurface, in- 

 cluding the under surface of the wings, darker. 



Measurements. — Males (10 from Bocas del Toro and Costa Rica), 

 wing 61.6-657 (63.7) , tail 29.2-33.2 (30.8) , culmen from base 19.4-21.6 

 (20.2), tarsus 23.3-25.2 (24.3) mm. 



Females (10 from Bocas del Toro and Costa Rica), wing 56.5-62.2 

 (60.6), tail 26.0-29.8 (27.8), culmen from base 18.2-22.0 (19.7), tar- 

 sus 22.2-24.2 (23.6) mm. 



Resident. Fairly common in damp woodland in western Bocas del 

 Toro, from the valley of the Rio Sixaola to near Almirante (mouth of 

 the Western River) ; and inland above the head of the Rio Changuena 

 to 730 m. 



This race has been found especially in the forests bordering Bahia 



