Note 77 — Family TYRANNIDÆ.—Tyrant Flycatchers.
Reading edition
Myiarchus tristis, var. nigriceps, Sclater. Myiarchus nigriceps, Scl. P. Z. S. 1860, 68, 295.—Coues, P. A. N. S. July, 1872, 75.
Obs.—The last three races appear to be all reducible to one species, as, taking the large series of specimens before us (over 30 skins), we find it impossible to draw the line between them. Specimens from Southern Mexico are referrible, with equal propriety, to lawrencei or to nigricapillus, while skins from Panama of nigriceps are less typical than those from Ecuador. This case of gradually increasing melanistic tendency as we proceed southward affords an exact parallel to that of Vireosylvia gilvus and V. josephæ, Sayornis nigricans and S. aquaticus, and many other cases.