84 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
containing a considerable number of specimens taken in Arizona by Dr. Mearns 
and now belonging to the American Museum. In addition my own collection 
has supplied some thirteen specimens of calwrus from various parts of the west- 
ern United States. 
On examining Mr. Frazar’s birds, twenty-eight in number, in connection 
with this material I have become convinced that so far as color and markings 
are concerned they cannot be separated from calurus, for every one of them 
may be closely matched by one or more of the specimens from Arizona, 
Colorado, or California ; while even as series the birds of the two regions show 
no obvious differences except in size, those from the United States averaging 
slightly larger than those obtained in Lower California by Mr. Frazar. 
Buteo borealis var. lucasanus was originally described by Mr. Ridgway ! as 
differing from B. calurus in having “ the upper parts more uniformly blackish, 
and the upper tail-coverts and tail uniform rufous, the latter without a trace of 
a black bar.” 2 
On examining the tail of the specimen (No. 16,925 Smith. Cat., Cape St. 
Lucas, Sept. 15, 1859; J. Xantus) from which this description was taken I 
find, however, very decided indications of a dark subterminal band. This is 
represented by a transverse series of short, narrow, blackish bars more or less 
broken and confused, mainly confined to the inner webs of the feathers and in 
no instance continuous across both webs. The black is rather faint on most of 
the feathers, but on some of the inner ones is perfectly distinct, and on one of 
them is really sharply defined and very conspicuous, forming a solid bar, .15 
of an inch in width, which extends from the shaft of the feather three quarters 
of the distance across its inner web. Of the outer pair of feathers one is 
apparently without any dark color near its tip, but both, as well as all the other 
rectrices, have a varying number of rather large black spots on one or both 
webs near the shafts, towards their bases. The tail of the type specimen (No. 
17,212 Smith. Cat., San Nicolas, Oct. 1859; J. Xantus) lacks all trace of 
these basal spots and at first glance appears to be perfectly plain towards the 
tip, also, but close inspection under a strong light reveals innumerable minute, 
dusky spots which, when the tail is spread, prove to be arranged in a regular 
transverse series forming a faint, but unmistakable subterminal band. The 
other three specimens labeled by Mr. Ridgway as B. lucasanus are immature 
and do not differ from calurus in corresponding plumage. . 
The majority of Mr. Frazar’s birds possess tail-bands quite as well-defined 
and conspicuous as in typical calurus, but in several of them the black is more 
or less broken and indistinct while at least two have the band scarce better 
marked than in the Smithsonian specimen, No. 16,925. With this specimen 
1 Baird, Brewer, and Ridgway, Hist. N. Amer. Birds, III. 1874, 285. 
2 In the Manual N. Amer. Birds, 2d ed., 1896, 233 Mr. Ridgway apparently 
abandons all of these characters except that of the color of the tail. In another 
connection (Proc. U. S. Nat. Mus., V. 1883, 544) he has expressed doubts as to 
whether the “ principal character assigned to ‘/Jucasanus’ (the uniform rufous tail 
without subterminal black bar) will prove constant, even in birds from the cape.” 
