22 PROCEEDIls^GS OF THE NATIONAL MUSEUM vol.74 



e.' Wings, tail, and upper parts in general more grayish 

 (yellowish olive only in Basilcuterus culioivorus yod- 

 mani). 

 f.' Superciliaries, sides of the head, etc., more grayish. 



Basileuterus cabanisi. 

 f." Superciliaries, sides of the head, etc., more yellowish. 



Basileuterus culicivorus. 

 d.' Sides of the throat black, continuous with the auriculurs. 



Basileuterus basilicus. 

 A.' Pileum rufous or chestnut, with conspicuous superciliaries, but no median 

 coronal stripe, 

 b.^ Pileum chestnut, with a narrow lateral line black, 

 c.^ Sides of head black to greenish dusky. 



d.* Superciliaries sti*aw yellow Basileuterus ignotus. 



d.^ Superciliaries white. 



e.' Above darker (olivaceous black) Basileuterus beusoni. 



e.' Above lighter (brownish olive) Basileuterus melanogenys. 



c.^ Sides of the head chestnut, like the pileum Basileuterus belli. 



b.* Pileum plain rufous, without a narrow black lateral line. 



Basileuterus delattrii. 



BASILEUTERUS MESOLEUCUS ScIaUr 



Basileiiierun mesoleucus Sclater, Proc. Zool. Soc. London, 1865. p. 286, pi. 9, 

 fig. 1 (Demerara, British Guiana; orig. descr. ; type in coll. Brit. Mus.). — 

 Shabpe, Cat. Birds Brit. Mus., vol. 10, 1885, p. 402 (Demerara and Kama- 

 kusa, Briti-sh Guiana; descr.; refs.). — Salvin, Ibis, 1885, p. 203 (Kama- 

 kusa, British Guiana) ; 1886, p. 506 (range). — von Berlepsch and 

 Habteet, Nov. Zool., vol. 9, 1902, p. 11 (Suapure, Venezuela). — M^negaux, 

 Bull. Mus. d'Hist. Nat., 1907, p. 496 (French Guiana; crit.).— von 

 BnaiLETscH, Nov. Zool., vol. 15, 1908, p. 108 (Approuage and Ipousiu, 

 French Guiana; Rio Carimang, British Guiana; ParS, Brazil). — Penaru, 

 Vogels van Guyana, vol. 2, 1910, p. 489 (Brit. Guiana; descr., etr.). — 

 Snethlage, Bol. Mus. Goeldi, vol. 8, 1914, p. 483 (Pan'i, Peixe-B<»i, and 

 Santo Antonio do Praia. Brazil; descr.). — Chubb, Birds Brit. Guiana, 

 vol. 2. 1921, p. 418 (British Guiana localities and refs.; descr.). 



Basileuterus rivul<ins mesoleucus Hexlmayr, Ahhand. K. Bayerischen Akad. 

 Wiss., Math.-phys. Kl., vol. 26, 1912, p. 86 (Santo Antonio do Prata, 

 Brazil). 



Description. — Pileum iron gray, passing into dull dark citrine on 

 the upper parts, the rump and upper tail-coverts a little brighter; 

 wings and tail externally like the back ; short superciliaries and sub- 

 ocular region ochraceous tawny, and auricular region tinged with the 

 same color; transocular stripe iron gray; underparts white, more or 

 less washed with buffy, especially on the breast, sides, and crissum: 

 under wing-coverts old gold ; " iris gi'ay, feet light yellow-orange, bill 

 white and black" (Klage;?). 



Some few specimens show traces of deep rusty margins to the 

 wing-coverts — probably an indication if immaturity. Young birds 

 in Juvenal dress (Tumatumari. British Guiana, July 25 and August 

 5) resemble the adults, but are much duller and browner above, with 



