TICHODROMA. 517 



Genus TICHODROMA. 



Both Brisson and Linnaeus included the Wall-Creeper in the genus 

 Certhia. In 1811 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 Palsearctic 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 crevices of walls. Its habits, food, nest, &c. will be fully described 

 in the following article. 



