Phasianus colchicus and its Allies. 171 



Phasianus principalis. 



This Pheasant is only known from the basin of the Mur- 

 ghab river. 



It is an intermediate form between P. persicus and P. 

 shawi. It differs from the former in having the rump and 

 upper tail-coverts glossed with brick-red instead of purple- 

 lake^ and the dark margins and tips of the feathers both of 

 the upper and underparts broader and more lustrous. From 

 the latter it differs in having less green below the neck on 

 the upper or underparts. On the centre of the breast and 

 belly no trace of green can be detected, even when the light 

 falls upon the bird from the back of the observer. Some 

 examples of P. shawi almost, but apparently never quite, 

 lose this trace of green. 



Phasianus shawi. 



This Pheasant is only known from the basin of the Kashgar 

 river, in the west of Chinese Turkestan. It is very nearly 

 allied to P. priticipalis, and is only prevented from inter- 

 breeding with it by the impassable plateau of the Pamir, 

 which effectually separates the two races. Typical examples 

 of each are most easily distinguished by the colour of 

 the margins of the feathers of the breast, especially the 

 lower breast, which is red or purple in the western race and 

 green in the eastern race. Occasionally, however, some of 

 the Kashgar Pheasants lose almost all trace of green on the 

 underparts below the neck; but the much narrower dark 

 margins of the feathers, especially on the mantle and flanks, 

 prevent them from being mistaken for P. principalis. 



But though P. shawi is prevented from interbreeding with 

 P. principalis or with P. chrysomelas by its geographical 

 position, it interbreeds with P. mongolicus, or, to speak more 

 accurately, with the race of that subspecies inhabiting the 

 basin of Lake Ebi. The strain of the latter species shows, 

 itself in a more or less imperfect white collar and in the 

 greater amount of green on the underparts. One of these 

 mongrels was described by Mr. D. G. Elliot (Proc. ZooL 

 Soc. 1870, p. 404) as P. insigtiis, and figured as a good species- 



