360 Mr. H. E, Dresser on some of the 



XXXI. — Notes on some of the rarer Western Paleearctic 

 Birds. By H. E. Dresser, F.L.S., F.Z.S. 



The study of ornithology has the great advantage of being 

 practically endless, and every year opens out fi-esh fields to 

 the student. Fresh material tends always to throw some 

 new light on the subject, and however carefully an article 

 may have been written, a lapse of a few years is sure to bring 

 forward fresh facts rendering it necessary to largely revise, 

 if not to re-write the information. When, in 1874, 1 prepared 

 the article on Sylvia melanocephala in the ' Birds of Europe,^ I 

 deemed it advisable to unite with that species both S. momus 

 and S. mystacea. In 1880 I ascertained that S. momus 

 would have to be specifically separated from S. melanocephala, 

 but from lack of material I decided to keep S. mystacea with 

 it. Mr. Seebohm, the following year, in the Brit. Mus. 

 Catalogue, followed my example. Since then, however, I 

 have received three examples of the true S. mystacea from 

 Dr. G. Radde, and have examined several other specimens. 

 This fresh material has clearly demonstrated to me that 

 S. momus and S. mystacea are specifically diff'erent. The 

 old male of S. momus has the crown and nape of a very deep 

 black, the division between the black and the grey of the 

 back being very sharp and clear ; the underparts are very 

 white, with the very faintest vinous tinge on the abdomen, 

 whereas the old male of S. mystacea has the crown and nape 

 dull black, this colour gradually merging into the grey of 

 the back on the nape ; the chin and a line bordering the 

 black (which extends below the eye as in S. momus) are pure 

 white ; the throat and breast are pale chestnut or dull vinous 

 red, gradually fading on the abdomen to white, the flanks, 

 however, being very pale reddish. 



Sylvia momus is extremely close to S. blanfordi, of which 

 only one specimen, the type, is known, and appears to differ 

 chiefly in having the rectrices margined and tipped with 

 white, the under surface of the tail in S. blanfordi being 

 nearly black, and in having the legs yellowish brown, 

 whereas in S. blanfordi they are said to be dark bluish grey. 



