622 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



basally, the basal phalanx of the middle toe being joined for most of 

 its length to the outer toe and for about half its length to the inner toe, 

 while in all the others the fusion extends for much less than the entire 

 length of the phalanx on the outer and for less than half its length 

 or the inner side. 



KEY TO THE SPECIES OF OPORORXIS. 



a. Tail not longer than distance from bend of wing to tips of secondaries, nearly 



even; outermost (ninth) primary not longer than sixth; bill more slender. 



b. Throat and chest yellow; top and sides of head with more or less of black, and 



with a yellow line extending from nostril to above, behind, and beneath eye. 



(Eastern United States; south in winter to Cuba and through Mexico and 



Central America to Colombia. ) Oporornis formosa (p. 622 ) 



hh. Throat and chest not yellow; top and sides of head without any black; no yel- 

 low on sides of head; a whitish orbital ring. (Eastern United States and 

 more southern British provinces; Bahamas and northern South America in 

 winter. ) ( Oporornis agilis. ) 

 c. Chin, throat, and chest gray, darker on chest. 



Oporornis agilis, adult male (p. 625) 

 cc. Chin and throat pale brownish or l)ri)wnish white; i-hest deeper brownish. 

 Oporornis agilis, adult female and immature birds (p. 626) 

 aa. Tail longer than distance from bend of wing to tips of secondaries, decidedly 

 rounded; outermost (ninth) primary longer than sixth; bill stouter. 

 b. Head and neck slate-gray, with more or less of black on throat and chest. 

 ( Adult males. ) 

 c. No white on eyelids; more black on chest, but less on lores. (Eastern North 

 America; south in winter through Central America to Colombia. ) 



Oporornis Philadelphia, adult male (p. 628) 

 cc. A white mark on each eyelid; less black on chest, l)ut more on lores. (West- 

 ern North America; south in winter through IMexico and Central America 



to Colombia. ) Oporornis tolmiei, adult male ( p. 631) 



bb. Chin and throat pale gray, grayish white, or pale yellowish, without any black; 

 lores grayish. (Adult females and immature birds. ) 

 c. Chin and throat pale gray or grayish white. 

 d. No white on eyelids; tail averaging 46.7. 



Oporornis Philadelphia, adult female (p. 628) 

 dd. A white mark on each eyelid; tail averaging 52.1. 



Oporornis tolmiei, adult female (p. 631) 

 cc. Chin and throat pale yellowish. 



d. Tail shorter Oporornis Philadelphia, innnature female (p. 628) 



dd. Tail longer Oporornis tolmiei, immature female (p. 631 ) 



OPORORNIS FORMOSA (Wilson). 

 KENTUCKY WARBLER. 



Adult male {irJioh (/Kir^). — Pileuni black, the feathers of crown and 

 occiput (especiall}^ the latter) tipped with slate-gray; rest of upper 

 parts, including sides of neck, plain olive-green; outer web of outer- 



ij am unable to discover the slightest difference between midwinter (January) 

 specimens and those taken in svunmer, except that the plumage, being more recently 

 acquired, is softer, and the slate-gray tips to the feathers of crown and occiput are 

 rather broader, these being sometimes quite worn away in midsummer specimens. 



