THRYOPHILUS. 



129 



amount of rusty brown on the sides ; the sides of the head and neck 

 more streaked with black. These differences are, perhaps, not in- 

 compatible with an identity of species, but the Guatemalan bird 

 differs from both in some decided characteristics. 



A fine adult Guatemalan specimen, received from Mr. Salvin, has 

 the under parts ashy-white, the flanks almost pure ashy. The under 

 tail coverts are white, banded sharply with black. In all the more 

 southern specimens before me, the under parts are more yellowish- 

 white, the flanks conspicuously pale rufous ; the white interspaces 

 of the black crissal bars more suffused with rusty. The legs of the 

 Guatemalan bird appear to be shorter, and the bill lower and smaller. 



The following diagnosis may serve to illustrate these differences. 

 In all the specimens the upper parts are bright reddish, or cinnamon 

 brown, less vivid towards the head; the wings and exposed surface 

 of the tail with black bands, much narrower than their interspaces. 

 The upper tail coverts without bands. Beneath white, without any 

 bands, except on the crissum, which is broadly marked with black. 

 A white line from bill over eye, and a brown one behind narrowly 

 margined with black ; the sides of the head with the white feathers 

 edged with black ; a black line from lower edge of lower jaw bor- 

 dering the chin : — 



Var. Tufalbus. — Beneath clear white ; the sides washed with reddish-brown ; 



black bands on tail about half the width their intervals. 

 Var. poliopleura. — Beneath ashy-white ; sides ashy without rusty wash ; 



black bands on tail about one-third their intervals. 



As already suggested, the Bogotan bird differs from both the pre- 

 ceding, though most closely allied to the former. 



(93, rufalbus, Panama.) Total length, 5.80 ; wing, 2.80 ; tail, 2.45 ; length 

 of bill from forehead, .86, from nostril, .53, along gape, .97; tarsus, 1.02; 

 middle toe and claw, .88. 



(30,656, poliopleura.) Total length, 5.90 ; wing, 2.70 ; tail, 2.50 ; length of 

 bill from forehead, .80, from nostril, .48, alcng gape, .91 ; tarsus, .93 ; middle 

 toe and claw, .80. 



9 September, 1864. 



