Note 16 — INTRODUCTION.
Reading edition
In the genus Ampelis and part of the Vireonidæ it is so extremely short as to appear absent, and is displaced, lying concealed outside the second (apparently first) primary, like one of the primary coverts; however, it may always be detected on close examination, differing from the coverts with which it is associated in some points of size and shape, if not also of color.