218 ALLEN'S NATURALIST'S LIBRARY. 



tary bristles, as in most Warblers, but in Hypolais these are very 

 small, and all but obsolete. The tail is only slightly rounded. 

 In the two species which are found in Central Europe the colour 

 of the under surface is yellow, but in all the other species of the 

 genus the tints are of the plainest description, being brown or 

 grey, with the under surface white. These plain-coloured 

 species, however, never approach the shores of England, and are 

 not likely to occur here, but of the two yellow-breasted species 

 of Europe, one has been found within our limits, and the other, 

 H. polyglotta, is an inhabitant of Western France, and might 

 easily occur in England. It may, therefore, be worth while to 

 mention that the two species may be distinguished by the pro- 

 portions of the primaries. In H. icterina the second primary 

 (i.e., the first long one) reaches a point between the fourth and 

 fifth, and in H. polyglotta it extends to between the sixth and 

 seventh. In the latter bird the legs are pale brown instead of 

 bluish-grey, and the first, or bastard, primary is long, and exceeds 

 the primary-coverts by o'i to 0*25 inch, whereas in H. icterina it 

 is generally shorter than the primary coverts, and never extends 

 more than 0*05 inch beyond them. 



THE COMMON TREE-WARBLFR. HYPOLAIS HYPOLAIS. 



Motacilla hypolais, Linn., Syst. Nat, i., p. 330 (1766). 

 Hypolais icterina, Newt. ed. Yarr., i., p. 361 (1873); Dresser, 



B. Eur., ii., p. 321, pi. 81 (1874) ; Seeb., Cat. B. Brit. Mus., 



v., p. 77 (i88i);B. O. U. List Br. B., p. 17 (1883); 



Lilford, Col. Fig. Br. B. pt. iii. (1886); Saunders, Man., 



p. 69 (1889). 

 Hypolais hypolais, Seeb., Hist. Br. B., i., p. 381 (1883). 



Adult Male. General colour above olive-green, the head like 

 the back ; lesser and median wing-coverts like the back ; the 

 greater series, primary-coverts and quills light brown, edged with 

 ashy-olive, a little yellower on the primaries, the inner secon- 

 daries with very pale margins ; tail-feathers light brown, with 

 olive-green edges, and with a narrow whitish fringe along the 

 inner web and round the tips in fresh feathers ; ear-coverts a 

 little paler than the back ; lores dusky, surmounted by a yellow 

 eye-stripe, which extends from the base of the bill behind the 

 eye ; eyelid and under surface of body yellow, deepening on 



