394 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
tipped with green or dusky; lateral rectrices extensively white, at 
least on inner web. Adult males with under parts bright metallic 
green, the under tail-coverts white; females with under parts pale 
gray or grayish white, glossed with green on sides. 
Range.—Southern Mexico to western Panamé. (Three species.) 
KEY TO THE SPECIES OF EUPHERUSA. 
a. Under parts (except under tail-coverts) metallic green. (Adult males.) 
b. Only two pairs of lateral rectrices with white on inner webs, the outer webs 
black or partly black. 
c. Outermost rectrices with outer web wholly black. (Hupherusa eximia.) 
d. Smaller (wing averaging 58.7, tail 33.5, culmen 17.6); line of demarcation 
between black and white on inner web of lateral rectrices sharply defined, 
nearly transverse. (Guatemala to Nicaragua.) 
Eupherusa eximia eximia, adult male (p. 394). 
dd. Larger (wing averaging 60.7, tail 34.7, culmen 18.7); line of demarcation 
between black and white on inner web of lateral rectrices indistinct, 
oblique. (Southeastern Mexico.) 
Eupherusa eximia nelsoni, adult male (p. 396). 
cc. Outermost rectrices with outer web white next to shaft, the edge black. 
(Costa Rica and western Panam4.) 
Eupherusa egregia, adult male (p. 396). 
bb. Four pairs of rectrices with white on inner web, the outer web and tip of inner 
web gray. (Southwestern Mexico.) 
Eupherusa poliocerca, adult male (p. 397). 
aa, Under parts dull white or pale gray. (Adult females.) 
b. Lateral pair of rectrices with a broad blackish tip, extending entirely across 
both webs and including shaft. 
Eupherusa eximia eximia, adult female (p. 395).¢ 
bb. Lateral pair of rectrices white, including tip, narrowly edged, in part, with 
dusky, the shaft entirely white. 
c. Middle rectrices bronzy passing into dusky terminally; outermost rectrix 
white, the outer web edged terminally with dusky; second rectrix broadly 
margined for terminal half with black. 
Eupherusa egregia, adult female (p. 397). 
cc. Middle rectrices bronze-green narrowly margined with dusky; outermost 
rectrix white, the outer web narrowly edged subterminally with dusky, the 
second similar, but with dusky subterminal spot on edge of inner web. 
Eupherusa poliocerca, adult female (p. 398.) 
EUPHERUSA EXIMIA EXIMIA (Delattre). 
STRIPE-TAILED HUMMING BIRD. 
Adult male.—Above bright metallic grass green, usually becoming 
more bronzy posteriorly, the upper tail-coverts sometimes distinctly 
bronze; middle rectrices dark bronze-green or greenish bronze; two 
lateral rectrices (on each side) with outer web black, faintly glossed 
with bronzy, inner web pure white very broadly and abruptly tipped 
with black; remaining rectrices with outer web dark bronze or bronze- 
green, inner web black; primaries purplish dusky, the innermost with 
@ The female of E. e. nelsoni not seen. 
