18/2.] MR. W. E. BROOKS ON THE IMPERIAL EAGLE. 503 



They belong to two distinct species, Aquila crassipes, Hodgson, 

 and Aquila bifasciata, Gray and Hardwicke. 



The former (A. crassipes) has three well-marked stages : — 

 1st. Light brown plumage, lineated both above and below. Each 

 feather possesses a light fulvous central stripe. The tail is, as a rule, 

 plain dark brown with a light tip ; and it is not barred. 



2nd. A very dark, black-brown plumage, both above and below, 

 save the upper part of the head and nape, which are buff or fulvous. 

 The tail changes to blackish brown, or nearly black, the upper part 

 being barred with grey, and the end having a broad 4-inch band of 

 black. The top of the head has also generally a patch of brown. 



3rd. The same as the second stage, with the addition of snow-white 

 scapulars, to a greater or lesser extent. 



I am correct in stating that the striped bird passes directly to the 

 old black-brown bird with light head, and am not advancing a theory 

 of my own ; for Mr. Anderson, of Futtehgurh, has shot two half- 

 changed birds, which he has kindly lent to me. These have numbers 

 of the lineated feathers still remaining intermixed with greater num- 

 bers which are black-brown. I believe a change of colour in these 

 feathers takes place without a moult. The tail of one bird is partly 

 changed (by a moult) to the adult tail with grey bars and dark ter- 

 minal band. 



Our second species (A. bifasciata) appears only to have two well- 

 marked stages. 



1st. The whole bird is a very pale dull grey-brown, sometimes 

 speckled slightly with fulvous on the abdomen. There are two broad 

 fulvous wing-bars, formed by the broad light tips of the greater 

 coverts and those of the secondary quills. The tail has also a light 

 tip, and is generally slightly barred with hoary grey. 



2nd. The very pale brown changes to a rather darker brown (which 

 is still but a dull light-toned brown compared with that of mature 

 A. crassipes) ; the wing-bars disappear, and the tail is strongly 

 marked with wavy grey bars on a dark brown or black ground. 

 There is no dark terminal band, but the barring is continued to the 

 end of the tail. 



The only further change towards maturity in this Eagle which 1 

 have seen, is, that the back of the head and nape of the neck become 

 buff-coloured or fulvous. The head then resembles that of the mature 

 A. crassipes ; but the brown of the body is not half so dark, being a 

 sort of earthy brown, " soil-brown," as Mr. Hodgson expresses it. 



Mr. Hodgson has two drawings of this Eagle — one in the first stage 

 (typical A. bifasciata), and the other in what I take to be the mature 

 bird with buff nape. He has another drawing, termed " A. nipalen- 

 sis," which is clearly intended to represent a very pale example of 

 A. bifasciata in its first stage. I possess a bird almost as pale. 



He has two drawings of the striped bird which he terms " Aquila 

 crassipes;" and I know of no other name which this Eagle bears. 

 The drawings are remarkably accurate. 



In coming to the conclusion that we had two Indian Imperial 



