150 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



A male, taken March 3, 1963, at Armila, eastern San Bias, had 

 the iris light gray ; cutting edge of maxilla and entire anterior half of 

 mandible neutral gray; rest of maxilla and cutting edge of distal half 

 of mandible black ; tarsus, toes, and claws dark neutral gray. 



Females, taken at the same locality, like male. 



Measurements. — Males (4 from Darien and San Bias), wing 69.8- 

 72.5 (71.1), tail 59.1-69.2 (63.8), culmen from base 18.8-19.5 

 (19.2), 22.2-22.3 (22.2) mm. 



Females (7 from Darien, San Bias, and Choco), wing 69.1-72.9 

 (71.0), tail 61.0-64.6 (62.7), culmen from base 19.3-21.0 (20.2), 

 tarsus 22.0-22.9 (22.3) mm. 



Resident. Known from a few individuals taken in the tropical 

 forests on the lower slopes of Cerro Tacarcuna in eastern Darien, 

 and in the foothill region of eastern San Bias. 



This interesting bird was described by Dr. Frank M. Chapman 

 from a male in the American Museum of Natural History, collected 

 by D. S. Ball, with the Harold Anthony Expedition on March 27, 

 1915, on the upper Rio Tacarcuna in eastern Darien. In early March 

 1963, I secured a pair in heavy undergrowth in forest covering the 

 foothills inland from the Cuna Indian village of Armila in eastern 

 San Bias. The birds did not range near the main small stream 

 draining this area, but instead lived along the narrow, steeply sloping 

 side valleys leading down into it. We had worked here intensively 

 for 10 days until chance brought the two mentioned. With this in- 

 formation, by careful search in similar terrain, we secured two addi- 

 tional pairs. 



On June 14, 1963, Dr. Pedro Galindo secured a female in a mist 

 net at La Laguna, the crater lake at 575 meters on a ridge leading 

 to Cerro Tacarcuna, and the year following, on March 8, I collected 

 another at the type locality on the Rio Tacarcuna, also in a mist net. 



The birds range in pairs in undergrowth in forest like some of the 

 common ant-shrikes, but more secretively. We had only momentary 

 glimpses of them in such cover, and I heard no calls that I could 

 attribute to them. 



Beyond the above, there are two females in the Academy of Natural 

 Sciences collected July 26, 1940, on the low mountain range of the 

 Serrania de Baudo in central Choco, inland from the Pacific coast 

 of northwestern Colombia. 



Though in general appearance these birds suggest species of the 

 genus Thamnophilus, their characters are such as to indicate their 



