634 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Sylvia pMlctdelphia (not of Wilson) Audubon, Orn. Biog., v, 1839, pi. 399. 



Geothlypis pliUaddjiliia Scl.vter, Cat. Am. Birds, 1862, 27 (Orizaba, Vera Cruz). 



Geothlypis [undetermined] Baird, Review Am. Birds, 1865, 227 (Dueiias, Guate- 

 mala). 



Geothlypis ? Salvin, Ibis, 1874, 307 (Dueiias specimen identified as G. mac- 



gillivrayi). 



Genus SEIURUS S^A^ainson. 



Seiurus Swainson, Philos. Mag., new ser., i. May, 1827, 369. (Type, MolaciUa 



aurocapilla Linnaeus. ) 

 Siiirus (emendation) Strickland, Ann. and Mag. Nat. Hist., vi, 1841, 422. 

 Enicocichla Gray, List Gen. Birds, 1840, 22. (Type, Motacilla aurocapilla 



Linnaeus. ) 

 Henicocichla (emendation) Cabanis, Mus. Hein., i, 1850, 15. 

 Exochocichla (emendation?) Van der Hoeven, Handb. der Zool., ii, 1852-56, 537. 



Similar in form to Oj?orornk, but tail even or slightly emarginate 

 (instead of rounded), and coloration very different, the under parts 

 conspicuously streaked with dusk}' on a white or pale yellowish ground. 



Bill shorter than head (nearly as long in S. motacilla), not essentially 

 different in form from that of Dendroica, but with middle portion of 

 culmen sometimes faintly depressed and with the lower outline of the 

 mandible more prominent or "bulging" at gonydeal angle. Nostril 

 and rictal bristles as in Dendroica and Oporornis. Wing long, pointed; 

 three to four outermost primaries abruptly longest, the ninth usually 

 longer than sixth (usually longer than seventh, except in S. aurocapil- 

 lus), sometimes longest; wing-tip longer than tarsus (except in jS. auro- 

 capiUus, in which it is shorter). Tarsus less than one-third as long as 

 wing (much less in S. novi'hoi'acensu), its scutella indistinct (obsolete 

 or fused on outer side); middle toe with claw nuich shorter than tar- 

 sus; basal phalanx of middle toe united for moi'e than half its length 

 to outer toe, separated nearly to base from inner toe. 



Coloration. — Above plain olive, greenish olive, grayish brown, or 

 sooty, the pileum sometimes (in one species) three-striped; beneath 

 white or pale yellowish, conspicuousl}' streaked with grayish brown 

 or blackish. 



Nidification. — Terrestrial. 



Itange. — North America; Mexico, Central America, West Indies 

 and northern South America in winter. (Three species.) 



KEY TO THE SPECIES AND SUBSPECIES OP SEIURUS. 



a. Pileum with two black stripes inclosing a l)road metlian stripe of orange-rufous 

 ochraceous, or tawny; a whitish orbital ring; no dusky loral nor postocular 

 streak, nor white or yellowish superciliary stripe. (Eastern North America, 

 south in winter to West Indies and through Mexico and Central America to 

 Chiriqui. ) Seiurus aurocapillus (p. 635) 



aa. Pileum unicolored (olive or sooty brown); no white orbital ring; a dusky loral 

 and postocular streak, and a white or yellowish superciliary stripe. 



