_Vireo cassini_, XANTUS, Pr. A. N. S. Phil. May, 1858, 117.—BAIRD,
Birds N. Am. 1858, 340, pl. lxxviii, fig. 1; Review Am. B. I,
1865, 347 (sub _V. solitaria_), RIDGWAY.
SP. CHAR. Third and fourth quills nearly equal, fifth shorter, second
longer than seventh. Spurious primary very narrow, falcate, acute;
less than one third the second quill, and a little more than one
fourth the third. Above, including edges of wing and tail-feathers,
clear olive-green, becoming dusky ashy on the top and sides of head.
Beneath fulvous-white, tinged with ill-defined olive-green on the
sides (scarcely on the crissum). Two broad bands on the wing-coverts
and the outer edges of the innermost secondaries greenish-white; the
outer edge of outer tail-feather, with a broad ring round the eye,
extending to a frontal band, dull white. Length about 5 inches; wing,
2.75; tail, 2.30.
HAB. Fort Tejon, Cal. (XANTUS); West Humboldt Mountains, Nevada
(RIDGWAY).
Since the type of this variety was obtained, two other specimens (Nos.
53,418 ♀ and 53,419 ♂, September, 1867; R. Ridgway) have been secured
by the United States Geological Survey of the 40th Parallel, in
command of Mr. Clarence King, in the West Humboldt Mountains, Nevada.
These specimens are even more different from true _solitarius_ than is
the type of this race, showing that it is really distinct, as a
variety. In the same thickets at the same season, perfectly typical
specimens of _V. solitarius_ were obtained; the latter having, no
doubt, come from their more northern summer home on their passage
southward into Mexico.
In the Humboldt Mountain specimens the crown shows no trace of ash,
and is even darker and more brownish than the back. In fact, the
relation of the _V. cassini_ to _V. solitaria_ is an almost exact
parallel to that of _V. josephæ_ to _V. gilvus_, as far as coloration
is concerned, in each case the extreme being widely different, but
connected by specimens showing intermediate characters.
Nothing is known of the habits of this race.
Lanivireo solitarius, var. plumbeus, COUES.