192 BRITISH BIRDS. 
Subfamily MOTACILLIN &, on WAGTAILS. 
The Wagtails and the Pipits are a group of slender-billed insectivorous 
birds. The absence of a bastard or first primary sufficiently distinguishes 
them from the Thrushes, Warblers, Tits, Crows, or Shrikes, and also from 
the Waxwings and Starlings, in which the bastard primary, though very 
small, is always present. From the Finches the slender bill is a 
distinguishing character, and from the Swallows the narrow bill and 
longer legs separate them sufficiently. 
The Larks, which are probably their nearest allies, differ in having the 
back of the tarsus scutellated, and in only moulting once in the year. 
The Wagtails and Pipits have a partial spring moult, which does not, 
however, extend to the quills and tail-feathers. In both genera the tarsus 
is scutellated in front. 
The Motacillinz are almost cosmopolitan, and are found throughout the 
world, except in the Polynesian Subregion, which consists of all the 
tropical Pacific islands. They are most abundant in the Palzarctic, 
Ethiopian, and Oriental Regions, and least so in the New World. Only 
one species of Wagtail enters the New World, in the extreme north-west 
of the Nearctic Région ; but the Pipits are rather more numerous. There 
are upwards of eighty species and subspecies in this group of birds, which 
has been subdivided into numerous genera, many of which are founded 
upon characters of a more or less trivial nature. Highteen species are 
found in the Western Palearctic Region, fourteen of which are included 
in the British list. Of these, two have been included on insufficient 
evidence. 
Genus MOTACILLA. 
The genus Motacilla, as defined by Linnus in the twelfth edition of 
his ‘Systema Nature,’ vol. i. p. 328, published in 1766, was a very com- 
prehensive one, including the Robins, the Accentors, the various groups of 
Warblers, some of the Flycatchers, the Chats, the Wagtails, the Wrens, 
