FAMILY TYRANNIDAE 507 



under surface of secondaries cinnamon-buff, changing to whitish on 

 the primaries. 



An adult male, taken at Mandinga, San Bias, February 12, 1957, 

 had the iris light wood brown ; maxilla black ; mandible flesh color ; 

 gape, inside of mouth, and tongue bright honey yellow, with two 

 elongate, dusky spots on either side of the premaxillar area, anterior 

 to the inner narial opening ; tarsus and toes dull neutral gray. In an- 

 other male (from the form of the wing still in its first year of age) 

 collected at the old Tacarcuna village site, Darien, March 7, 1964, the 

 iris was orange brown, the maxilla black, mandible ivory white, tarsus 

 and toes brownish neutral gray. A female, at the mouth of the Rio 

 Tuquesa, Darien, March 28, 1959, had the iris brownish orange; 

 maxilla black; mandible flesh color; gape and inside of mouth, in- 

 cluding the tongue, rather dull orange (without the spots described 

 in the adult male) ; tarsus and toes neutral gray. 



Measurements. — Males (10 from Code, Colon, Province of Pa- 

 nama, Darien, and San Bias), wing 88.7-97.1 (93.4), tail 78.5-86.5 

 (82.2), culmen from base 17.8-18.8 (18.3), tarsus 17.9-18.9 (18.5) 

 mm. 



Females (10 from Code, Canal Zone, Province of Panama, and 

 Darien), wing 71.3-76.1 (73.4), tail 62.8-67.8 (65.8), culmen from 

 base 16.5-17.8 (17.2), tarsus 16.5-17.6 (16.9) mm. 



Resident. Uncommon, in forested areas in the Tropical Zone ; on 

 the Pacific slope from the southern Canal Zone and Chepo eastward 

 through Darien ; on the Atlantic side from the valley of the Rio Indio 

 (El Uracillo, northern Code; Chilar, western Colon) eastward 

 through San Bias. 



Usually these birds rest quietly in the undergrowth on low perches 

 where they may be partly concealed among leaves. They may allow 

 close approach, and, unless attention is attracted by the curious, 

 explosive call, may not be seen. The note has a trilling, or rattling 

 quality that is difficult to describe. While frequently alone, they also 

 are found in pairs, when, if seen clearly, the larger size of the males is 

 obvious. Both sexes have a display, noted occasionally, in which one 

 wing is extended straight up, full length above the back, like that 

 noted commonly in Pipromorpha. The female, as stated, is appre- 

 ciably smaller than the adult male. Males in their first year may be 

 smaller than those fully adult. 



Dr. Alexander Skutch (in litteris 10/15/70) has kindly sent me 

 the following account of an observation of this species, on Barro 

 Colorado Island : 



