Note 125 — Family PICIDÆ.—The Woodpeckers.
Reading edition
A character common to all the members of the genus, and distinguishing them from the species of every other; this peculiar form of the middle tail-feathers is caused principally by a folding of the webs downward, almost against each other. The under surfaces of the shafts have a very deep groove their whole length, which is seen in no other genus.