11. opoEOExrs. 347 



b'. Crown of head slaty grey, with black bases 



to the feathers; back olive-green formosa hiem., p. 349. 



c'. Crown of head olive or ashy brown ; back 



olive-green formosa juv., p. 349. 



b. Throat ashy grey ; breast pale yellow afftlis ad., p. 347. 



c. Throat pale riifescent brown ; breast pale yellow <7^i7/s jiiv., p. 347. 



1. Oporornis agilis. 



Svlvia agilis, JTl/s. Amer. Orn. v. p. G4, pi. 39. fig. 2 (1812) ; Audub. 



' B. Amer. pi. 138; id. Orn. Biogr. ii. p. 227 (1834). 

 Sylvicola agilis, /wrf. ed.Wih.Amer. Orn. i.p. 159 (1832) ; Bichards. 

 Be]). Brit. Assoc. 1836-37, p. 172 ; Audub. Si/n. p. 03 ; ul. B.Amer. 

 ii. p. 71, ph 99 (1841). 

 Trichas agilis, Nutt. Man. 1840, p. 463. 

 ? Trichas tephrocotis, Nutt. t. c. p. 462. 



Oporornis agilis, Baird, B. N. Amer. 1858, p. 246; id. op. cit. 1860, 



, Ann. Lye. 

 \, no. 3502 

 Bretcer, ^ 

 Midgtc. Hist. N. Amer. B. i. p. 290, pi. 15. -tigs. 1, 2 (1874) ; Cones, 

 B. Color. Vail. p. 308 (1878) ; Bidgtc. Bull. U.S. Nat. Mns. no. 21, 

 p. 18 (1881) ; Cones, Key X. Amer. B. 2nd ed. p. 309 (1884). 

 ? Geothlypis tephrocotis. Barn. Smiths. Bep. 1860-61, p. 435. 

 ? Oporornis varius, Blakist. Ibis, 1863, p. 61. 

 Geothlypis agilis, Gregg, Proc. Elmira Acad. 1870, p. 7 (teste Cones). 



Adult nude. General colour above duU olive-green, slightly yel- 

 lower towards the rump and upper tail-coverts ; lesser wing-coverts 

 like the back ; median and greater coverts, bastard-wing, and pri- 

 mary-coverts dusky, edged with olive-green ; quills dusky brown, 

 margined externally with lighter olive ; tail-feathers dusky brown, 

 washed externally with olive : crown of head dull ashv grey, the 

 occiput and nape olive-grecu like the back, the crown even slightly 

 washed with the same colour ; eyelid white, forming a conspicuous 

 ring : lores ashy grey : in front of and below the eye a line of dusky 

 blackish, somewhat overshading the anterior portion of the ear- 

 covcrts, which are otherwise slaty grey ; cheeks and entire throat 

 slaty grey ; fore neck and under surface of body pale sulphur-yellow, 

 including the under tail-coverts ; sides of body olive-greenish, as 

 also the thighs ; axillaries olive-yellow : under wing-coverts dull 

 olive, brighter yellow on the edge of the wing ; quills dusky below, 

 ashy along the edge of the inner web : " bill light brown on the 

 ridge and at the tip, flesh-coloured beneath ; legs pale flesh-colour ; 

 iris hazel "' {Audubon). Total length 5-4 inches, culmen 0-5, wing 3, 

 tail 2-05, tarsus O'So. 



In the spring birds the ash of the head and throat is quite pure 

 and very dark, almost black on the breast ; then the resemblance to 

 Geothhjpis Philadelphia is very close, but in the latter the wings are 

 little, if any. longer than the tail. (Coue.^.) 



Adult male in winter jdumaf/e. Differs from the spring plumage 

 in having the head olive like the back, the ear-coverts olive-brown, 

 and the cheeks and throat pale reddish brown, deeper and more 

 olive-brown on the fore neck ; otherwise as in spring. {Mus. Salvin 

 and Godman.) 



