MUSEUM OF COMPARATIVE ZOOLOGY. 329 



remarks that a single specimen in the Museum of the Philadelphia Acad- 

 emy is the only one he had seen "presenting the least appearance of 

 adult plumage." In regard to the size of the specimens of the two scries, 

 adopting the length of the folded wing as the basis of comparison, — the 

 besl clement in the tables available for comparison, in this respect, — the 

 smallest and the largest specimens, measuring 370 and 438 millimetres re- 

 spectively, occur in the B. borealis series. The average length of wing in 

 twenty specimens of B. borealis is 409 millimetres, and in fourteen * speci- 

 mens of B. Harlani Bryant, 405. The difference of 4 millimetres is an 

 amount too trivial to be of account, as the addition of a single specimen to 

 cither series might reverse the difference. Hence the impression possessed 

 by Dr. Bryant of an average difference in size between the two series 

 was evidently an erroneous one. 



There, hence remains but a single difference, that in respect to the form 

 of the wing, or the relative length of the primaries, by which to distinguish 

 the two series, which is at best one of doubtful value. My present opinion 

 is that all the so-called species of these two groups may be safely referred 

 to the original Buleo borealis, except the B. oxypterus, which should be un- 

 doubtedly referred to the B. pennsylvanicus, 



87.* Buteo lineatus Jardine. Red-shocldered Hawk. 



Falco lineatus Gmelin, Syst. Nat, I, 268, 1788. — Wilson, Am. Orn., VI, 



86, pi. liii, fig. 3, 1812. — Audubon, Orn. Biog., I, 296, pi. lvi, 1832. 

 Buteo lineatus Jardine, Am. Orn., I, 1832. — Audubon, Svn., 7, 1839. — 



Cassin, Baiid's Birds N. Am., 28, 1858. — Verrill, Proc. Essex Institute, 



III, 141, 1862. 

 Falco hyemalis Gmelix, Syst. Nat., I, 274, 1788. — Wilson, Am. Orn., IV, 



73, 1812. — Nuttall, Man. Orn., I, 106, 1832. — Audubon, Orn. Biog., 



V, pi. lxxi, 1832 (young). 

 Buteo Cooperi Allen, Amer. Nat., Ill, 518, 1869. 



Circus hyemalis Bonap., Journ. Phil. Acad. Nat Sci., 1st Ser , III, 305, It 

 Butto elegans Cassin, Proc. Phil. Acad. Nat. Sci., 1855,281. — Cassin, Baird's 



Birds of N. Am 28, 1858. 



Very abundant. By far the most numerous species of the family. 



Generally smaller and much brighter colored than New England speci- 

 mens. The dark line along the shaft of the feathers below, especially on 

 the throat and breast, is very distinct, in this respect and in the bright 

 colors greatly resembling the so-called Buleo elegans of Cassin. B. elegans, 



* The B oxypterus, referred to the B. Harlani by Bryant, is very much smaller than 

 any other specimen in either series, and it seems to me has decided affinities, in its 

 small size as in other features, with the B. pennsylvaniais, as stated by Mr. Cassin, 

 and it is hence excluded in my computation of the average length of the folded wing. 



