76 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [IH<, 



p. 68, where the following remarks, written by rae to Mr. Gurney, are 

 quoted : 



"It has been more than ten years since I saw the specimen in ques 

 tiou ; but my recollection of it is that it agreed very exactly with a speci- 

 men from Costa Rica and another from Buenos Ayres, both of which 

 are in the National Museum collection, and both of which are unques- 

 tionably young of typical B. swainsonV 



Having recently been enabled, through the courtesy of the author- 

 ities of the Philadelphia Academy, to make an actual comparison of 

 the three specimens involved in the above statement, and having found 

 the same to be incorrect, I wish to offer some remarks which may throw 

 more light on B. oxypteriis and its relationships. 



Although smaller than any example in the National Museum col- 

 lection, "i>. oxypterus^^ is unquestionably referable to B. swainsoni. ll 

 is a young bird, and probably a male. Dr. Bryant's statement (Pr. 

 Boston Soc. viii, 1861, p. 118) to the following effect is incorrect: 

 "Several of the primaries in both wings of this bird are only partially 

 develoj)ed, which gives the wing a peculiarly sharj) appearance." On 

 the contrary, the primaries are all full grown, their proportionate length, 

 compared with one another and with the secondaries, and all other 

 details 'of wing-structure, being exactly as in other specimens of B. 

 sicainaonL Mr. Cassin, in his original description, did not compare " B. 

 oxypterus,^^ with B. sivainsoni at all, but with B. pennsylvanicus, a species 

 very difterent in respect to its wing-formula, and in comparison with 

 which B. sivainsoni may very appropriately be termed "sharp-winged." 



In coloration, the type of *' B. oxypterns " does not resemble the Costa 

 Kica and Buenos Aires specimens so much as I had supposed. The lat 

 ter are much variegated with pale ochraceous on the upper parts, while 

 the former is nearly uniform above, the wings quite so. The nearest 

 approach among National Museum examples is No. 67248, a young male 

 from Camp Grant, Arizona (September 28, 1873, H. W. Henshaw), 

 which is much like it in the markings of the lower parts, though the 

 thighs are much less regularly barred; but the wing coverts are broadly 

 bordered with bull. It is likewise larger, the wing measuring 14.7.5 

 inches. 



Upon the whole, I cannot see the slightest reason for recognizing " B. 

 oxypterus^^ even as a local race of swainsoni^ the type being exceptional 

 as to size, while the average dilference in dimensions between northern 

 and southern specimens is insignificant. 



The specimen described in "History of North American Birds" (iii, p. 

 266), as the melanistic adult of '■'■ Buteo sicainsoni var. oxypterus" is not 

 B. sivainsoni at all, but B. fuliginosus, Scl., which is said (and proba- 

 bly with truth) to be the melanistic phase of B. hrachyurus, Vieill. 

 This I have been able to determine beyond question by an examination 

 of the wing formula, which is radically distinct in the two species, al- 



