FAMILY TYRANNIDAE 463 



found them common on Coiba and on Isla Rancheria in early October 

 1965. Two were taken by Morton on October 9. 



In the original description it was noted that these small flycatchers 

 were found usually on low perches in areas of open forest, where they 

 had clear view in their watch for small flying insects. When these 

 were sighted the bird darted out to seize them, often with a clearly 

 heard snap of the bill, and then turned gracefully to return to a 

 perch, often the one from which it had made its sally. They were 

 especially common along forest trails, and at times were found in the 

 thickets behind the coastal beaches. It was rare to note one in the 

 higher tree tops. At the time of my visit in January and early Febru- 

 ary they were silent. 



EMPIDONAX FLAVIVENTRIS (Baird and Baird) : Yellow- 

 bellied Flycatcher, Moscareta Barriga-Amarilla 



Tyrannula flavk'cntris W. M. and S. F. Baird, Proc. Acad. Nat. Sci. Phila- 

 delphia, vol. 1. nos. 2&-39, July-August (September 18), 1843, p. 283. (Carlisle, 

 Cumberland County, Pennsylvania.) 



Small ; greenish olive above, yellowish underneath, with a faintly 

 indicated dark band across the breast. 



Description. — Length 118-130 mm. Adult (sexes alike), upper 

 surface greenish olive, with crown somewhat darker; wing coverts 

 dull black, middle and greater coverts tipped broadly with yellowish 

 white ; distal ends of secondaries edged with yellowish white ; pri- 

 maries dull grayish brown, with slightly paler outer edges ; tail grayish 

 brown, with outer webs, and in some the tips paler ; lores mixed 

 yellowish white and dull gray ; a pale yellowish white ring around the 

 eye ; side of head like back, becoming paler on sides of neck and body ; 

 center of throat dull yellowish white, with the feathers faintly grayer 

 centrally ; upper breast light yellowish olive ; lower breast, abdomen, 

 and under tail coverts pale yellow ; axillars and under wing coverts 

 pale yellow, the outer coverts changing to dull gray ; inner webs of 

 wing feathers grayish buff. 



Measurements. — Males (10 in June, July, from northern New 

 York to Newfoundland), wing 65.2-68.5 (67.4), tail 51.2-54.9 

 (53.2), culmen from base 13.1-14.1 (13.7), tarsus 16.0-16.5 

 (16.2) mm. 



Females (10 in June, July, from northern New York to New- 

 foundland), wing 61.1-65.9 (63.4), tail 47.3-50.8 (49.5), culmen 

 from base 12.7-14.0 (13.3), tarsus 15.8-16.1 (15.9) mm. 



Winter resident, migrant from the north. Common on the Pacific 



