THE BIEDS OF MONGOLIA ETC. 291 



spots are formed. Wings blackish ; quills edged with white or yellow, the 

 secondaries having also a white tip and a white spot at the base of the 

 inner webs ; on the primaries the white spot at the base diminishes towards 

 the edge of the wing by degrees, and is hardly perceptible on the second 

 quill, the outer web of which is quite white, with the exception of its point ; 

 the first short quill is white. The upper wing- coverts dark brown, with 

 wide white edges, with the exception of the largest, which are quite black. 

 Under wing-coverts white. The two central tail-feathers are dark reddish 

 brown, with wide yellowish edges ; the others are black, with a broad white 

 band on the ends, which becomes narrower towards the centre and is hardly 

 perceivable on the fifth tail-feather. Upper tail-coverts light brown. Under 

 tail-coverts dirty white. Towards the spring the feathers rub very much, 

 and fade away a great deal — so much so, that the edges of the quills and the 

 upper tail-coverts become quite white. 



The female does not differ from the male bird in plumage. 



I have called this species after an ornithologist, Mr. W. H. Taczanowski, 

 of the Warsaw Museum. 



We met with this bird for the first time at the sources of the river 

 Tetunga, and found it very abundantly distributed in the Koko-nor steppes 

 and in Northern Tibet, avoiding the Tsaidam country. In its habits it 

 reminds one of the Chats, runs about very quickly, perches on stones or 

 small heaps, constantly bowing and vibrating its wings. 



The holes of a species of Lagomys, which is extremely numerous in the 

 Koko-nor steppes, serve these birds as an abode for the night, and probably 

 also for building their nests. In some instances the bird also digs its own 

 hole, at which work my companion once saw it. They often live in small 

 companies, but never form large flocks. 



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