Mr. R. B. Sharpe’s Catalogue of Accipitres. 327 
head the plumage is blackish brown; the same hue pervades 
the interscapular feathers, and, when there is no rufous collar, 
the sides and nape of the neck also; the remainder of the 
upper surface, including the tail, resembles the corresponding 
parts in the white-breasted young birds, except that where 
the latter are partially white on the inner webs of the quill- 
feathers of the wing and on the upper tail-coverts, the dark- 
plumaged birds show a pale ferruginous tint replacing the 
white on those portions of the plumage. 
On the under surface these dark-coloured birds seem to 
be subject to considerable individual variation. 
In a bird of this complexion from Costa Rica, which is in 
the possession of Messrs. Salvin and Godman, and which I 
may call No. 10, the dark shaft-marks are broad on the centre 
and outer sides of the throat, and narrow in the intermediate 
space ; broader, again, across the crop, on the flanks, and on 
the thighs, as well as on the axillaries and under wing-coverts 
(where, however, they are palerin colour), and narrowon all the 
remainder of the underparts, except on the under tail-coverts, 
from which they are altogether absent. The Norwich Mu- 
seum possesses a very similar example from Trinidad ; and at 
pp. 85 and 36 of Léotaud’s birds of that island, two speci- 
mens are described which seem to have been of a character 
somewhat intermediate between the lighter and darker phases 
of plumage, and to have been also in course of change from 
immature to adult dress. 
I propose now to refer to the colour of the underparts in 
two other specimens belonging to Messrs. Salvin and God- 
man, of a similar character to No. 10, but darker on that 
portion of their plumage; these specimens I may enumerate 
as Nos. 11] and 12. 
In No. 11, which is from the southern slope of the volcano 
of Chiriqui, the shaft-marks are very much as in No. 10 on 
account of this species in the ‘Muséum des Pays-Bas,’ vol. i. Pernes, 
p: 9:—“ D’autres individus sont bruns en dessus, blanchatres en dessous, 
avec des taches longitudinales brunes plus ou moins étendues, cou avec 
un collier roux.” 
