114 PROCEEDINGS OF THE ACADEMY OF 



formula, 3-4-2-5-6-7-1, 8. Three outer primaries emarginated 

 on inner webs ; second, third, and fourth, sinuated on outer. 

 Wing, 13.70 ; tail, 7.00 ; tarsus, 2.10 ; middle toe, 1.35. Primaries 

 project bej'ond secondaries, 5.50. 



Female (33,508, San Jose, Costa Rica ; J. Carmiol) : l Differs 

 from the type chiefly in lighter colors. The whole forehead very 

 broadly immaculate dull white, this continuing back to the occi- 

 put in a broad unstreaked superciliary stripe; along the upper 

 edge of the ear-coverts is a rusty suffusion, with condensed, fine 

 dusky streaks, forming an indistinct stripe separating the wholly 

 white ear-coverts from the supraoral stripe; the " mustache" is 

 very conspicuous ; the breast has a few large tear-shaped spots of 

 clear blackish-brown, and the sides have very sparse, irregular, 

 and more sagittate spots of the same ; the whole posterior parts 

 are immaculate. The upper parts are more variegated with paler, 

 the wing-coverts and rump having the feathers irregularly border- 

 ed with whitish. The upper tail-coverts are white, barred with 

 dark brown. Tail, hoary brown, crossed by nine or ten nearly 

 obsolete, narrow bands of dusky. Whole lining of the wings im- 

 maculate, except the conspicuous patch on the primary coverts. 

 The whole under surface of the primaries is uniform slaty, gradu- 

 ally deepening into black towards ends. Wing-formula, 3-4-2-5- 

 6-7, 1. Wing, 15.00 ; tail, 8.00 ; tarsus, 2.45 ; middle toe, 1.55. 

 Primaries project beyond secondaries, 6.00. 



The specimen from Buenos A}Tes (No. 55,876, % juv., Conchi- 

 tas, November, 1868; Wm. H. Hudson) was labelled by Mr. 

 Sclater " B. albicaudatus," and so published (Proc. Zool. Soc, 

 Lond., 1869, 634). This species, however, though belonging 

 strictly to the same section of the genus with B. swainsoni, and 

 being in fact its nearest ally, is yet very distinct, having alto- 

 gether larger and longer tarsi. The National Museum contains a 

 fine suite of this species, illustrating the variations to which it is 

 subject. This specimen is exactly like the Costa Rican one just 

 described. 



1 Type of description in Baird, Brewer, and Ridgway's Hist. N. Am. 

 Birds (vol. III. p. 267) of B. swainsoni var. oxypterus. "i?. albonotatus" 

 Lawr., Ann. IV. 7. Lye. N. H., IX. Ap'l, 1868, 133 ! 



