420 SYLVIID^G. 



430. Acanthopneuste davisoni. The Tenasserim White-tailed 

 Willow- Warbler. 



Reguloides viridipennis (? BlytK), apud Wald. in Blyth Birds Bunn. 



p. 108. 

 Reguloides viridipennis (Blytli), apud Hume, S. F. \, p. 330 ; 



Hume fy Dav. S. F. vi, p. 358; Hume, Cat. no. 567; id. S. F. 



vii, p. 453, ix, p. 291, xi, p. 223. 



Phylloscopus viridipennis, Blyth, apud Seebohm, Cat.B. M. v, p. 53. 

 Phylloscopus presby tis (S. Miill!), apud Oates, B. B. \, p. 86 ; Brooks, 



Ibis, 1889, p. 576. 

 Acanthopneuste davisoni, Oates ; Oates in Hume's N. fy E. 2nd ed. i, 



p. 269. 



Coloration. Very similar to A. trochiloides, but differing in being 

 smaller and in having the inner webs of the two outside tail-feathers 

 white. 



Legs and feet rather pale brown ; soles yellowish ; upper man- 

 dible dark brown ; lower wax-yellow ; iris brown (Hume). 



Length about 4'3; tail 17; wing 2-1; tarsus '75; bill from 

 gape '55 ; the second primary is about equal to the tenth ; the 

 first primary is about '55 inch long. 



After a careful reconsideration of the synonymy of this species 

 I am reluctantly compelled to give it a name and I have much 

 pleasure in naming it after Davison, its discoverer. 



The history of the species is briefly this. In 1855 Blyth de- 

 scribed a Willow- War bier from Teuasserim under the name of 

 Phylloscopus viridipennis. He neglected to state what the colour of 

 the tail was ; an all-important matter. Davison, many years after, 

 procured a white-tailed Willow- Warbler in Tenasserim, and Hume 

 unhesitatingly identified it with P. viridipennis, Blyth. Against 

 this, we have Brooks's positive evidence that he examined Blyth's 

 types in Calcutta and found them to be the bird we know as 

 A. trochiloides. The opinion of Brooks on such a subject is in my 

 opinion conclusive. We also have Jerdon describing P. viridi- 

 pennis, Blyth, in the ' Birds of India,' as having an olive-green tail, 

 no mention being made of any white feathers, and he states that it 

 occurs at Darjiling. This locality coupled with the description 

 point to A. trochiloides ; for the Tenasserim white-tailed bird is 

 not know r n to occur in Sikhim. 



It must be borne in mind that Blyth's P. viridipennis is just as 

 likely to have been A. trocliiloides as the present species discovered 

 by Davison, for both species were found by Davison in Tenasserim, 

 the former in the Salween district, the latter on Muleyit mountain, 

 no great distance apart. For all these reasons therefore I reject 

 Blyth's name as inadmissible for the present form. 



In 1870 Blyth visited the Leyden Museum and there observed 

 a white- tailed Willow- Warbler which Miiller in 1835 had named 

 presbytis without a description. Leaving alone such a minor com- 

 plication as that of this bird being labelled " Timor," while Miiller's 

 bird came from Sumatra, it is to be noticed that this white-tailed 

 Acanthopneuste did not recall to Blyth any recollection of his Tenas- 



