BIRDS OF NORTH AND MIDDLE AMERICA. ^33 



()7-Ti (69); tail, o0-58 (57); exposed cuIiucik io-ib (!•'). 7); tar.sus, 

 23-L^i (23.5); middle toe, 16-16.5 (16.2)." 



J'^>?<?///.— Similar in color of upper parts to adults, Imt darker and 

 duller, especially on pileum; superciliary stripe narrower, less sharply 

 di^Hned, bi-ownish buffy; under parts dull j^rayisli white medially, the 

 cliest sparsely flecked with dusky; lateral under parts dull grayish 

 hrown, tino-ed with rusty browti or chestnut: under tail-coverts pale 

 rusty, ])arred with dusky. 



lliohlands of western Guatemala (Volcan de Fuego; Duenas; Savana 

 Grande; San Diego; Escuintla, Retalhuleu; Coban); Honduras? 



Thriothurus rnfaUms Lafresnaye, Rev. Zool., viii, 1845, 337 ("Mexico;" type 

 in coll. Boston Soc. Nat. Hist.; see Ridgway, Proc. Bost. Sec. N. H., xxiii, 

 1888, 386). 



Thryothoruit rnfalbns Bonaparte, Consp. Av., i, 1850, 221.— Sclater and Sai.vin, 

 Ibis, 1859, 8 (Duenas, Guatemala). 



[Thryopliilui''] rvfalbus Sclatek and Salvix, Noui. Av. Neotr., 1873, (>, part 

 (Guatemala). 



Thviiophiltis rufaUms Salvin and Godman, Biol. Centr.-Am., Aves, i, 1880, 82, 

 part (Volcan de Fuego, Duenas, Savana Grande, San Diego, Escuintla, Retal- 

 huleu, and Coban, Guatemala).— Sharpe, Cat. Birds Brit. Mus., vi, 1881, 

 212, part (Guatemala).— Salvin, Cat. Strickland Coll., 1882, 77 (Guate- 

 mala).— RirxiWAv, Proc. Bost. Soc. N. H., xxiii, 1888. 386 (remarks on type 

 specimen). 



Tlhnjoiihihis] rufalbus rufalhnx Hei>i,mavk, Verh. k. k. zool. -hot. (icseilsi-h. 

 Wien, 1901, 767, in text. 



Tlroglodytes] rufalbus Gray, jGen. Birds, i, 1847, 158. 



IThryothorus] poliopleura Batrd, Review Am. Birds, Aug., 1864, 122 (diagnosis). 



Thryophilus rufalbus, var. poliopleura Bairu, Review Am. Birds, Aug., 1864, 128 

 (Savana Grande, Guatemala; coll. U. S. Nat. Mus.). 



[Troglodytes] poliopleurus Gray, Hand-list, i, 1869, 190, no. 2599. 



Thryophilus rufalbus poliopleura GoovE, Bull. U. S. Nat. Mus., no. 20, 1883, 345. 



THRYOPHILUS RUFALBUS CASTANONOTUS Ridgway. 

 CHESTNUT-BACKED WREN. 



Similar to T. r. rufalhns, but black l)ars q\\ tail nmch broader, usually 

 more than half as wide as the chestnut interspaces on middle rectrices, 

 sometimes even wider; dusky bars on secondaries broader and darker 

 in color; dusky streaks on sides of head ])roader; sides and tlanks 

 ta\vny-])rown instead of grayish. 



.b^^/^;/.rtA-. -Length (skms), 130-162 (U3.<s); wing, 66-74 (70.1); 

 tail, 48-57.5 (52.1); expo.sed culmen, 18-21 (Il>.l); tarsus, 23.5-26.5 

 (24.3); middle toe, 15.5-17 (16).* 



Adult female.—luQnc^th (skins), 129.5-148 (140.6); wing, 64-76 



"Three specimens, including two of Lafresnaye's types; none of them with sex 

 determined. 



& Ten specimens. 



