96 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Measurements. — Males (10 from Darien, Panama; Antioquia and 

 Bolivar, Colombia), wing 64.2-66.9 (65.1), tail 55.1-58.2 (56.9), oil- 

 men from base 19.0-20.4 (19.5), tarsus 22.0-25.1 (23.7) mm. 



Females (10 from Darien, Panama; Antioquia and Bolivar, Colom- 

 bia), wing 58.2-61.8 (59.0), tail 50.3-54.6 (52.4), oilmen from base 

 17.8-20.4 (18.8), tarsus 20.7-22.8 (21.7) mm. 



Resident. Found locally in the Subtropical and upper Tropical 

 Zone of Darien on Cerro Pirre, Cerro Tacarcuna, and Cerro Quia (780 

 m) . The population of Panama, named by Griscom, is found to be the 

 same as that of western Colombia. 



Goldman recorded 1, taken at 1200 m above Cana, as ranging in un- 

 dergrowth along a ridge. The stomachs of 2 that he collected in late 

 May and early June were filled with fragments of beetles, hemiptera, 

 ants, gryllids, a caterpillar, and spiders. Ridgely (in litt.) observed a 

 pair foraging in undergrowth at the edge of forest with a mixed flock on 

 the slopes of Cerro Quia, Darien, at 540 m, rather lower than most 

 other Panama records. The birds were silent as they moved through 

 quite open lower undergrowth. In western Colombia, Hilty (Wilson 

 Bull., 1974, pp. 479-481) recorded it quite regularly at swarms of the 

 small army ant Labidus praedator. There is no record at present of the 

 nest and eggs. 



In a considerable series of specimens examined there is no indica- 

 tion of intergradation between T. spadix and Thryothorus atrogularis, 

 the two groups differing completely in details of the color pattern, nota- 

 bly in the crown and upper breast. Hellmayr (Cat. Birds Amer., part 7, 

 1934, p. 183) from limited material listed spadix as a geographic race 

 of atrogularis, an arrangement followed also by Paynter (in Check-list 

 Birds World, vol. 9, 1960, pp. 399-400). The series of both groups 

 now available shows no indication of conspecific relationship. Geo- 

 graphically the two groups are widely separated. 



S. West (in litt. to Eisenmann, October 1973) reports seeing a wren 

 on Cerro Azul, eastern Province of Panama, with a black throat, but 

 he failed to determine to which of these species it belonged. 



THRYOTHORUS FASCIATOVENTRIS Lafresnaye: Black-bellied Wren, 

 Cucarachero Vientrenegro 



Medium size; foreneck and throat pure white, rest of undersurface 

 black, partly barred white, upper surface reddish brown. 



Description. — -Length 135-150 mm. Adult (sexes alike), foreneck 

 and upper breast pure white, rest of undersurface black, banded nar- 

 rowly with buff or with white on lower breast, abdomen and undertail 



