FAMILY TYRANNIDAE 597 



(within the mouth) Hght bluish gray; tip of tongue dull yellowish 

 brown, with the base and the rest of the inside mouth lining dull 

 blackish slate. 



Measurements. — Males (10 from the Pacific slope of Costa Rica 

 and western Chiriqui), wing 60.0-64.7 (62.4), tail 46.3-52.3 (49.1), 

 culmen from base 13.0-15.0 (13.9), tarsus 15.2-16.2 (15.8) mm. 



Females (2 from Chiriqui). wing 55.4-56.7 (56.0), tail 42.0-43.8 

 (42.9), culmen from base 13.5-14.0 (13.7), tarsus 14.7-14.8 

 (14.7) mm. 



Resident. Found locally in western Chiriqui from Puerto Ar- 

 muelles, Santa Clara, and El Volcan to Divala, Boquete, and 

 Boqueron; to 1250 meters elevation around the base of Volcan 

 Baru. 



This darkest of the races ranges north in Costa Rica on the 

 Pacific slope. Slud (Bull. Amer. Mus. Nat. Hist., vol. 128, 1964, 

 p. 275) recorded it in that country in "small parties in the Pacific 

 northwest." 



The observations of Skutch (Pac. Coast Avif., no. 34, 1960, 

 pp. 561-570) on this species in western Costa Rica refer to the 

 present race. He speaks especially of one bird near El General 

 that "plucked a small, dark object from the foliage and, holding it 

 in the tip of his bill, placed it beneath his wing." This was an 

 instance of anting, as on examination he found ants from a small 

 nest crawling over the branches and leaves. 



In the early dry season in March males took stations in the under- 

 growth and lower tree crown, where for a period of several months 

 they called persistently zvhip wit chip chip chip chip, repeating this 

 steadily through the day. At the same time they display by flitting 

 the wings, one at a time, raising them above the back and then 

 folding them. Females are attracted, and after mating, build a nest, 

 deposit the eggs, incubate, and care for the young without assistance 

 from the male. The eggs, usually three, less often two, are white 

 without markings. The average size in 10 was 20.2 X 14.3 mm. The 

 young at hatching had a body covering of "sparse but fairly long 

 gray natal down." 



PIPROMORPHA OLEAGINEA ASSIMILIS (Sclater) 



Mioncctcs assunilis P. L. Sclater, Proc. Zool. Soc. London, pt. 27, May 1859, 

 p. 46. (Cordoba, Veracruz, Mexico.) 



Generally similar to P. o. dyscola, but larger ; above darker olive- 

 green ; crown averaging darker, more dusky, than the back. 



