9 2 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Three collected by Goldman May 25 to 30, 1911, had the stomachs 

 filled with fragments of beetles, other miscellaneous insects including 

 earwigs, egg cases of roaches, and spiders. 



This population of the wren is definitely an intergrade toward the 

 next form, schottii, of eastern Panama and Colombia. Transition be- 

 tween castaneus of the Caribbean slope of western Panama east through 

 the northern Canal Zone at the western end of its range is fairly abrupt. 

 Specimens from near Colon, and northern Canal Zone, are definitely 

 castaneus. Those from Portobelo, 30 km east, are reditus. At the 

 eastern end the type locality at Perme is barely within the range as 

 birds from Armila and Puerto Obaldia, between 15 and 20 km east, are 

 placed with schottii. 



THRYOTHORUS SEMIBADIUS Salvin: Riverside Wren, 

 Cucarachero Castano Cabecimoreno 



Thryothorus semibadius Salvin, Proc. Zool. Soc. London, November 1870, p. 181. 

 (Bugaba, Chiriqui, Panama.) 



Rather small; crown rufous-brown, like back (not black as in nigri- 

 capillus); rest of undersurface barred narrowly with black and white 

 (with 3 black bars on each feather) . 



Description. — Length 120-135 mm. Adult (sexes alike), crown, back, 

 scapulars, and upper tail coverts chestnut-brown; wings somewhat 

 brownish black, spotted and barred narrowly with light brown on the 

 exposed outer webs, the bars extending across both webs on the inner- 

 most feathers; lesser coverts black, spotted with white; tail dull black, 

 barred and dotted with brownish burl; side of head black, edged widely 

 with white, especially on the lores, superciliary line, and cheeks, which 

 are largely white; throat white; rest of undersurface, including the 

 underwing coverts, white, barred narrowly but heavily with black, the 

 white changing to brownish buff on flanks, lower abdomen, and under- 

 tail coverts; bend of wing white. 



Juvenile, somewhat duller brown above. 



A male, collected at Corotu, near the coast, northeast of Puerto 

 Armuelles, Chiriqui, February 9, 1966, had the iris light reddish brown; 

 cutting edge of maxilla and entire mandible neutral gray; rest of 

 maxilla black; basal area of inside of mouth black, with anterior half 

 of inner surface of maxilla and mandible neutral gray; tarsus, toes, and 

 claws neutral gray, with the inner surface of tarsus somewhat paler. 



Measurements. — Males (10 from Chirqui), wing 60.1-66.6 (63.3) 

 tail 44.6-50.6 (46.4), oilmen from base 19.1-20.6 (19.8), tarsus 22.4- 

 25.4 (23.5) mm. 



