THE TREE-WARBLERS. 
217 
sat down upon a tree-trunk to watch. The bird was very un- 
easy, but continually came back to a birch tree, from which it 
frequently made short flights towards the ground, as if it were 
anxious to return to its nest, but dare not do so whilst we 
were in sight. This weiat on for about half an hour, when we 
came to the conclusion that the nest must be at the foot of the 
birch-tree, and we commenced a second search. In less than 
five minutes I found the nest, with six eggs. It was built in a 
slight tuft of grass, moss and bilberries, semi-domed, exactly 
like the nest of our Willow-Warblers.” 
Nest. — Composed of dry grass and moss, and lined with rein- 
deer-hair, according to Mr. Seebohm. 
Eggs. — The above named author describes these as having the 
ground-colour pure white, spotted very thickly at the large end, 
in the form of an irregular zone, with reddish-brown, and more 
sparingly on the remainder of the surface ; some of the spots 
underlying and paler, but not grey, and on one or two of the 
eggs they are confluent. Axis, o - 6 inch ; diam., 0-45. Mr. 
Seebohm remarks: “The markings are well-defined, like 
those on the eggs of the Chiffchaff ; but the colour is decidedly 
more like that of the Willow-Warblers, while they approach 
much more closely the eggs of the Indian Willow- Warbler, P. 
humii, both in colour and size.” 
THE TREE-WARBLERS. GENUS HYPOLAIS. 
Hypolais, C. L. Brehm, Isis, 1828, p. 1283. 
Type, H. hypolais (L.). 
Certain groups of Warblers have a typical coloration of 
egg, known to every ornithologist. Thus anyone can tell the 
peculiar egg of a Cettia, which is of a brick-red colour, and this 
style of coloration runs through the eggs of all the species 
allied to Cetli’s Warbler. The same may be said of the mem- 
bers of the genus Hypolais , for the eggs of these birds are 
equally peculiar, having the ground-colour of a purplish-grey or 
salmon-pink. All the members of the genus are like Willow- 
Warblers in general aspect, but they have a much longer and flat- 
ter bill, approaching that of the Reed-Warblers ( Acrocephalus ) in 
shape, and havingthree weak rictal bristles, with some supplemen- 
