VO l889."'] PROCEEDINGS OF THE NATIONAL MUSEUM. 31 



Costa Eica, belonging to the Costa Rica National Museum. These show 

 a considerable amount of individual variation, the two young birds from 

 Costa Eica being particularly unlike, one resembling the Panama spec- 

 imen described, though considerably darker above and less tinged with 

 tawny beneath, while the other (No. 2334, male, San Carlos, December 

 25, 1888, A. Alfaro) is very much darker throughout, the under parts 

 being mainly of a dark sepia-brown. 



Sclerurus olivascens Cabanis. 



Sclerurus olivascens Cab., Jour, fur Orn., Jan., 1873, 67 (Monterico, W. Peru). — Tac- 

 zan., P. Z. S., 1874, 526 (Monterico) ; Orn. du Pe"rou, n, 1884, 115. 



Hab. — Western Peru. 



Sp. Char.* — " Nearly uniform olive-brown; the breast more olive; 

 throat whitish, undulated with olive; tail black." (Taczan., Orn. du 

 Perou, ii, 1884, 115; translation.) 



"Female adult. — General plumage of a dusky fuliginous-olive, the 

 olive clearer on the under parts, especially on the breast ; middle of the 

 throat whitish, undulated with olive. Wings of the same color as the 

 back ; tail blackish. Bill brown, the lower mandible paler, whitish un- 

 derneath ; feet brown ; iris deep brown. 



" Length of the wing, 95; tail, 70; bill, 24; tarsus, 23 millimeters." 



" Observations. — A form similar to the preceding [S. umbretta], the 

 bill shorter and straighter, the general color more uniform, the rump 

 concolor with the back." (Taczanowski, I. c; translation.) 

 Smithsonian Institution, June 29, 1889. 



* The original description, by Cabanis (I. c), translated, is as follows : " In general 

 resembling the Brazilian Sc. umbretta, with somewhat longer wings (94 mm ). It differs 

 in coloring by the want of the brownish red rump, which is uniformly colored with 

 the other upper parts. The rusty reddish tinge to the whole plumage is replaced by 

 a brownish olive color. Throat mixed with whitish. Hab. Monterico. Female. The 

 male is still unknown. The female is characterized in all the species by the whitish 

 throat. In the Brazilian S. umbretta the male has a rusty red throat. So. ruficollis 

 Sws., which Gray considers identical with S. mexicanus, is the male of S. umbretta. 

 On the other hand, the very similarly colored mexicanus is to be considered as the 

 male of a somewhat smaller variety." 



It may be remarked regarding the alleged sexual differences in color that, so far as 

 I am aware, no other author appears to hold views similar to those expressed by Pro- 

 fessor Cabanis. The circumstance that S. mexicanus inhabits the combined areas of 

 several other species is of itself sufficient to disprove them, while even more convinc- 

 ing is the fact that in the series of specimens of the two Middle American species (S. 

 mexicanus and S. guatemalensis), both sexes, according to the determinations of the 

 collectors, are represented in each. 



