620 MR. A. ANDERSON ON THE [May 7, 



we have two distinct birds, viz. Aquila crassipes (of Hodgson's un- 

 published MS. and drawings) and Aquila bifasciata. 



I should, however, premise by stating that Aquila imperialis 

 (vera), Cuv., would appear to be quite distinct, as already pointed 

 out by Mr. Howard Saunders*, and tbat it is questionable whether 

 this species has as yet occurred in India. 



My endeavours towards procuring specimens of these two Eagles 

 in transitional stages have been crowned with success, and I am 

 now in a position to prove beyond doubt that two species have 

 hitherto been confounded in the fourfold stage described by Humef 

 (as surmised in my former communication), each of them having 

 what appear to me three well-marked stages. 



I shall characterize them separately, as briefly as possible. 



1. Aquila crassipes (Hodg. unpublished MS.). The Indiani 

 Imperial Eagle. 



Under this time-honoured name§, which I propose being retained 

 for this species, now separated for the first time, Hodgson has figured 

 two lineated birds corresponding with Hume's first stage of Jerdon's 

 Imperial Eagle. The figures have been most artistically executed, 

 and agree in every detail with the lineated birds which visit the 

 plains of India in such numbers during the cold season. 



During the months of December and January last I was fortunate 

 enough to shoot a pair of Eagles, male and female, passing direct 

 from the lineated to the black-brown stage, which eventually obtains 

 white scapulars; or, in other words, Hume's first and. fourth stages 

 are referable to this species — his second and third to the sister Eagle, 

 which is the true Aquila bifasciata. 



My friend Mr. Brooks has favoured me with the following de- 

 tailed description of these two birds : — 



" No. 1 . A. crassipes clearly shows that the lineated bird passes 

 direct into the black-brown one, which eventually gets white scapu- 

 lars. The upper part of the back and lower neck above still retain 

 the light-centred feathers so characteristic of the lineated stage. 

 The tail retains some of the plain brown feathers almost without 

 markings of any kind, which tail-feathers are characteristic also of 

 the lineated stage. Many of the secondaries and tertials are those 

 of the young bird. Below the plumage is a mixture of black-brown 

 and brownish white or fulvous. Many of the feathers about the 

 breast are light-centred ones, as also the neck-hackles ; other fea- 

 thers have the central and apical portions dark brown. I am not 

 quite sure but that the change to black-brown occurs, not by a moult, 

 but by a gradual change of colour in the feather, commencing with 

 the tips ; sometimes working with regularity up the centre of the 

 feather, at others affecting one side more than the other. The tibial 

 plumes of this bird are fulvous white, mottled with dark brown ; 



* P. Z. S. 1871, p. 38. 



t Eough Notes, Part I. pp. 147-151. 



| I add the word Indian in contradistinction to the true imperialis. 



§ Hodgson's MS. and drawing is dated 1838. 



