370 BULLETIN 50, UNITED STATES NATIONAL MUSEUM, 
green; under tail-coverts grayish centrally. (Northern and western Mexico 
and southern Arizona.).......... Cynanthus latirostris, adult male (p. 370). 
ce. Smaller, with relatively shorter bill (wing averaging 51.7, culmen 18.2), 
back and rump bronze; chin and throat emerald green or slightly bluish 
green; under tail-coverts dusky centrally. (Tres Marias Islands.) 
Cynanthus lawrencei (p. 373). 
bb. Tail forked for more than one-third its length; wing, 46-51; exposed culmen, 
16.5-19.5; forehead and crown brilliant metallic blue or bluish green. (South- 
western Mexico.).....-..-..2-2+----------0+ Cynanthus doubledayi (p. 375). 
aa. Under parts brownish gray; rectrices metallic green basally, blue-black subter- 
minally, the lateral ones tipped with brownish gray. (Adult females.) 
b. Wing 49.5-54, averaging much more than 50; culmen 19-23.5, averaging much 
more than 20; tail slightly emarginate. 
c. Lateral under parts with little of green; basal portion of rectrices brighter 
POST 5 2..cr8 ase deste Gates sc Cynanthus latirostris, adult female (p. 370). 
ce. Lateral under parts conspicuously spotted or washed with metallic green; 
basal portion of rectrices darker and duller green. 
Cynanthus lawrencei, adult female (p. 374). 
bb. Wing 45-49, averaging 47.2; culmen 18-19.5, averaging 18.5; tail deeply emar- 
PlNate, os seers recreate Cynanthus doubledayi, adult female (p. 375). 
CYNANTHUS LATIROSTRIS Swainson. 
BROAD-BILLED HUMMING BIRD. 
Adult male—Above metallic bronze-green, usually duller on 
pileum, where sometimes passing into dull grayish brown on forehead; 
tail glossy blue-black or dark steel blue, the four middle rectrices 
tipped (more or less broadly) with deep brownish gray, the remaining 
rectrices sometimes narrowly margined with the same; remiges 
dusky brownish gray or dull slate color, faintly glossed with purplish, 
the outermost primary narrowly edged with pale gray or grayish 
white; chin and throat bright metallic greenish blue or bluish green 
(the color more blue anteriorly, more green posteriorly), passing into 
metallic bronze-green on breast, sides, flanks, and abdomen; under 
tail-coverts dull white, usually more or less distinctly grayish cen- 
trally, the shorter ones sometimes with dusky, slightly metallic, spots; 
anal tufts and tuft on each side of rump white; bill brownish (pur- 
plish red or carmine in life), dusky terminally; iris dark brown; feet 
dusky; length (skins), 88-105 (92); wing, 49-57 (51.6); tail, 28-36 
(32.3), the middle rectrices 23-29.5; culmen, 18.5-22 (20.4).* 
Adult female——Above similar in color to adult male but duller, 
especially on pileum, which is usually dull grayish brown or brownish 
gray anteriorly; remiges paler grayish brown; middle pair of rec- 
trices bronze-green passing into blue-black or greenish black termi- 
nally (the extreme tip sometimes green or bronzy); other rectrices 
with basal half (more or less) bronze-green, the remaining portion 
blue-black tipped with brownish gray (most broadly on lateral pair); 
under parts sooty gray or dark drab-gray (browner than mouse gray), 
6 Thirty-one specimens. 
