WHITE-BACKED COPURUS 



dd. Grayish below; yellowish margins to wing 



quills but no distinct bars 



Tyranniscus vilissimus parvus 



cc. Of more slender build; abdomen canary yellow. 



d. Chest yellowish olive, throat gray; crown 

 dusky with patch; two conspicuous wing 

 bars Tyrannulus elatus reguloides 



dd. Under parts almost wholly yellow. 



e. Very minute, with short tail; white line 



over eye; no wing bars 



Microtriccus b. brunneicapillus 



ee. Larger; tail fairly long; yellow line over 



eye; two yellow wing bars 



Capsiempis flaveola semiflava 



i. Copurus leuconotus Lafresnaye 

 White-backed Copurus 



Male. Length 228 mm. (9.00 in.) ; tail (elon- 

 gated middle feathers) 162 mm. (6.40 in.). 

 Plumage generally black, the head sooty gray 

 margined on forehead and sides by a broad 

 band of white, the back broadly streaked with 

 grayish white, middle of abdomen whitish. 

 Two middle tail feathers narrow and greatly 

 elongated. 



Female. Length 197 mm. (7.80 in.); tail 

 (elongated middle feathers) 129 mm. (5.10 in.). 

 Similar in color to male; tail shorter. 



A forest species. It sits on a branch and flies 

 out repeatedly to catch an insect, returning to 

 the same perch. "Gatun. In a flock of about 

 ten on a dead sapling in a clearing." (Hallinan.) 



285 



