326 BULLETIN OF THE 



referred by Bonaparte to his B. Swainsoni, but has since been recognized 

 as a valid species by Cassin and other recent American authors. In 

 1853 Mr. P. It. Hoy described a Buteo Bairdii, and in 1854 Mr. Cassin 

 added B. insignatus, in 1855 B. calurus and B. oxypterus, and in 1856 B. 

 Cooperi. In 1861 Dr. Bryant made a revision of the group, then contain- 

 ing eight or nine species currently recognized by American ornithologists, 

 and reduced the number of species to two, one of which he called B. 

 borealis and the other B. Harlani; which latter, however, is not the 

 Harlani of Cassin, and probably not the Harlani of Audubon. 



Dr. Bryant, in the above-cited paper, describes in detail the leading 

 variations presented by our red-tailed hawks, and the character of the 

 numerous supposed species of this group that had then been recently 

 described. He having at his command all the specimens of this group con- 

 tained in the Museums of the Philadelphia Academy and the Smithsonian 

 Institution, including the original types of Mr. Cassin's species, as 

 well as the specimens in his own collection, his opportunities lor investi- 

 gating the subject were unusually favorable. The results of his exam- 

 ination of this material may be briefly stated in his own words. He says 

 that after examining this large series of specimens, he found " that of all 

 those belonging to Harlani, insignatus, Swainsoni, Bairdii, oxypterus, 

 borealis, montanus, calurus, and perhaps Cooperi," could be "easily reduced 

 to two very distinct groups, each of which is distinguishable by definite 

 external characters, and in which the variations of plumage, though 

 apparently so great, if the extremes of the series only are taken into con- 

 sideration, can, it seems to me, be arranged in a series, in which the 

 connecting of the different members may be readily traced. Of these two 

 groups, or rather species, one, which should be called B. borealis, as the 

 first described, consists of that species, montanus, calurus, Harlani, and 

 probably Cooperi, and is characterized by a very muscular body,* stronger 

 and longer bill, longer and more powerful tarsi, and a more rounded wing, 

 the fourth quill generally the longest, tin- fifth little if any shorter than 

 the third, anil the first always longer than the eighth. The other species, 

 to which Harlani?, insignatus, Swainsoni, Bairdii, and oxypterus belong, is 

 distinguishable by a more slender body, shorter and weaker tarsi, and a 

 more pointed wing, the third quill generally the longest, the fifth consid- 

 erably shorter than the third, and the first always longer than the eighth." 



" On making the examinations which led to the conclusion above stated," 

 he further observes, " I was struck by tin- small number of specimens in 

 which all the feathers were equally developed, and when they were so, 

 the variation in the proportions of the primaries, and of the wings and 



* Stuffed skin> evidently ruTord rather unsatisfactory data for the determination of 

 the relative muscularity of the body. 



