612 APPENDIX. 
(98.) Page 568, after Regulus satrapa olivaceus: 
An adult male of R. satrapa from the city of Mexico in Mr. Lawrence's 
collection is much deeper and richer colored than even Pacific coast examples, 
and no doubt represents a race resident on the high mountains of central 
Mexico, which Mr. Lawrence has named, in manuscript, Regulus satrapa aztecus. 
The lower parts are light grayish brown, or drab, the underlying portion of the 
plumage pale dull buffy; the white superciliary stripe (tinged with brownish 
anteriorly) is much more conspicuous than usual, owing to contrast with the 
very dark color of adjacent portions of sides of head and brownish lower parts ; 
the secondaries and rectrices are edged with very bright yellowish olive-green, 
while the back, scapulars, and rump are a rather dull olive-green, changing to 
dull sooty grayish on the hind-neck. Wing 2.25, tail 1.70. 
(99.) Page 569, after P. czerulea: 
751a. Polioptila cerulea obscura Ripaw. Western Gnatcatcher.’ 
Similar to P. cerulea, but darker and less blue above; lores darker; super- 
ciliary streak less distinct ; white on tail-feathers more restricted. Hab. South- 
western United States (California, Arizona, etc.) and western Mexico. 
(100.) Page 581, Sialia mexicana requires subdivision, as follows: 
ce. Chestnut color of back extremely variable in amount, sometimes entirely 
absent, but in the latter case the chestnut of the breast continuous 
anteriorly. 
d'. Back usually (?) with little if any chestnut; blue of upper parts of a 
rich deep “smalt” hue; wing in adult males averaging 4.38. Hab. 
Highlands of southern Mexico. 
S. mexicana Swains. Mexican Bluebird. 
d’, Back usually with much chestnut, often wholly so, very rarely with a 
mere trace; blue of upper parts varying from rich ultramarine to 
light eobalt; wing in adult males averaging 4.07. 
é. Back with median portion more or less blue, the chestnut usually 
in form of lateral patches, rarely reduced to a mere trace on 
each side. Hab. Pacific coast, from British Columbia to southern 
California, east to western Nevada, casually, during migrations, 
to New Mexico...... 767. S. mexicana occidentalis (Towns.). 
Western Bluebird.’ 
é. Back wholly chestnut. Hab. Rocky Mountain district, and south 
into northern Mexico......... 767a. S. mexicana bairdi Rivew. 
Baird’s Bluebird. 
1 Polioptila cerulea obscura Ripew., Proc. U. S. Nat. Mus. v. March 21, 1883, 535, foot-note. 
2 Sialia occidentalis Towns., Journ. Ac. Nat. Sci. Philad. vii. 1837, 188.—Sialia mexicana occidentalis 
Rivew., Auk, xi. April, 1894, 151, 154. 
8 Sialia mexicana bairdi Ripew., Auk, xi. April, 1894, 151, 157. 
