PHYLLOSCOPUS. | 4.23 
Genus PHYLLOSCOPUS. 
The Willow-Warblers were originally included by Linneeus in his genus 
Motacilla, and were afterwards separated hy Scopoli and placed in his 
genus Sylvia together with the rest of the Warblers. In 1802 Bechstein 
created the subgenus dAsi/us in his ‘ Crnithologische Taschenbuch,’ p. 178, 
for the reception of the Willow-Warblers; but as, in 1767, Linneus had 
already applied that name to a genus of insects in his ‘Systema Nature’ 
(i. p. 1006), it cannot be also applied to a genus of birds. In 1816 Koch, 
in his ‘ System der baierischen Zoologie,’ i. p. 158, made an equally unsuc- 
cessful attempt to erect a genus for the reception of the Willow- Warblers, 
selecting for this purpose the name of Ficedula, a name which is open to 
three objections: In the first place, the Motacilla ficedula of Linneeus is 
not a Willow-Warbler, whatever else it may be; in the second place, in 
1799 Cuvier made a genus Ficedula to contain the Flycatchers ; and, in the 
third place, the genus Ficedula of Brisson appears to be synonymous with 
the genus Motacilla of Linnzus, and its type was probably a young or 
female Pied Flycatcher. In the following year Forster, in his ‘ Synoptical 
Catalogue of British Birds,’ p. 54, was equally unfortunate in adopting the 
specific name trochilus, which Linneus gave to the Willow-Warbler, as 
the name of his new genus, regardless of the fact that this name had 
already been applied by Linnzeus (Syst. Nat. i. p. 189) to the Humming- 
birds. In 1826, however, Boie succeeded in finding a name which is open 
to no objection, and in the ‘Isis’ for that year (p. 972) established the 
genus Phylloscopus for the Willow-Warblers, making P. trochilus the 
type. 
The Willow-Warblers are a group of about five-and-twenty little birds 
so nearly allied to the typical Warblers (Sy/via), the Tree-Warblers 
(Hypolais), the Reed-Warblers (Acrocephalus), the Grasshopper Warblers 
(Locustella), and the Grass-Warblers (Lusciniola), and especially to the 
Indian Flycatcher Warblers (Adrornis), that it is impossible to draw a 
hard and fast line between any of these genera, except by arbitrarily 
choosing some character and making it the standard of separation. In 
such nearly allied genera, where the intermediate species have not yet 
become extinct, ornithologists must accept with gratitude any cha- 
racter, however trivial, which seems to classify the species into natural 
groups. 
The principal characteristic of the Willow-Warblers is their semi- 
