36 FALCONID A. 
croach on the brown, which becomes merely a central 
blotch, indented on each side by the white ; while in aged 
birds the plumage is mostly pure white, varied only by a 
few narrow transverse bars on the upper parts.” 
These coinciding observations from two distinguished 
naturalists render any attempt at a technical description 
unnecessary, beyond adding that the specimen from which 
the present figure was taken measured twenty-three inches 
in length from the point of the beak to the end of the tail : 
the beak itself pale bluish horn colour, the cere yellow: 
the irides dark, as are those of all the true Falcons: the 
head, neck, chest, under surface of the body, and under 
tail-coverts, become pure white before the greyish brown 
spots and bars are lost on the back and upper surface of 
the wings; the wing-primaries are dark at the tip, but 
do not reach to the end of the tail: the tarsi and toes 
are yellow ; the claws black, curved, and sharp. 
