TICHODROMA. 517 
Genus TICHODROMA. 
Both Brisson and Linneus included the Wall-Creeper in the genus 
Certhia. In1811 Illiger removed it and established the genus Tichodroma 
for its reception in his ‘ Prodromus systematis Mammalium et Avium,’ 
p- 210. As this was the only species known to Illiger, it must therefore 
be the type. 
The peculiar style of coloration of this species is a sufficient generic 
distinction to separate it from the allied groups of Certhia and Sitta. 
From Certhia it may at once be distinguished by the tail-feathers, which 
are rounded and soft, not pointed, and from Sitta by its slender beak ; and 
from both of these genera it also differs in having the wing-coverts and part 
of the primaries rich crimson. The bill is long, slender, and somewhat 
curved ; the tail is rounded; the wings are long and broad; the gape is 
not furnished with any rictal bristles; the tarsus is scutellated; and the 
feet are armed with strong claws, to enable the bird to firmly grasp the 
rocks. 
But one species of Wall-Creeper is known. It is confined to the 
southern portions of the Palearctic Region, in the west not crossing the 
Mediterranean, but in the east encroaching upon the Oriental Region in 
the Himalayas and China. It appears to have only twice wandered as far 
as the British Islands. 
The Wall-Creeper is closely allied to the true Creepers (Certhia), and 
appears to bear the same relation to that genus as the Rock-Nuthatches 
do to the Tree-Nuthatches. Unlike the true Creepers, it frequents rocks 
and mountain-ranges, searching for its food in the clefts and fissures and 
in the erevices of walls. Its habits, food, nest, &c. will be fully described 
in the following article. 
