the western part. Wetmore (1948:185-186) examined a
series of Golden-fronted Woodpeckers that showed a definite cline in
dorsal coloration from north-central Texas to Jalisco, Michoacan, and
Hidalgo in south-central Mexico. He (_loc. cit._) stated that "the
extremes are easily separable, but in southern and southwestern Texas
and in northeastern Mexico the two kinds [_C. a. aurifrons_ and _C. a.
incanescens_] ... merge so gradually that over a broad area the whole
population is intermediate, making decisions as to any sharply drawn
dividing line difficult and in part arbitrary." _C. a. incanescens_,
according to Wetmore, occurs in western and central Texas south to
northeastern Chihuahua and northern Coahuila whereas _C. a. aurifrons_
occurs in north-central Coahuila (Monclova) and southern Texas south to
Jalisco, Michoacan, Hidalgo, and central Tamaulipas.

The specimens that I have examined from Coahuila are variably
intermediate between the subspecies _aurifrons_ and _incanescens_. The
dark and white cross-bars on the back of No. 31039 are nearly equal
(dark bands wider in _aurifrons_; white bands wider in _incanescens_);
the rump and upper tail coverts are more or less mixed with black as in
_aurifrons_. The dark cross-bars on the backs of Nos. 32054-32057 are
slightly larger than the white cross-bars; the rump and upper tail
coverts of these specimens are somewhat mixed with black.

*_Centurus aurifrons incanescens_ Todd.--This subspecies of the
Golden-fronted Woodpecker is listed by Miller, Friedmann, Griscom, and
Moore (1957:34) from "... northern Coahuila (upper Rio Grande valley)."
Burleigh and Lowery (1942:192) stated that the Golden-fronted
Woodpecker "apparently avoids the mountain slopes, but was found to be
not uncommon on the arid plateau about Saltillo." Findley saw
Golden-fronted Woodpeckers 2 mi. W Jimenez, 850 feet, on June 19, 1952;
and 2 mi. S and 3 mi. E San Juan de Sabinas on June 22, 1952. Cory
(1919:424) listed the Golden-fronted Woodpecker from Sabinas. Nos.
32055-32057 are juveniles, and thus document breeding by this
woodpecker in Coahuila.

*_Melanerpes formicivorus formicivorus_ (Swainson).--_Specimens
examined:_ total 5: [Male] 31040 (skeleton only) from Fortin (=33 mi.
N, 8 mi. W San Geronimo), 3300 ft., March 28, 1952; [Male] 29423 and
[Female] 29424 from Club Sierra del Carmen (=2 mi. N, 6 mi. W Piedra
Blanca), 4950 ft., April 8, 1950; [Female] 31041 (skeleton only) from
26 mi. W Sa