BIRDS OF NORTH AND MIDDLE AMERICA. 363 
Range.—Guatemala to Colombia and Venezuela. (Two species. ) 
While closely resembling, superficially, the type species of Aphan- 
tochroa Gould, this genus differs in relatively longer tail (more, 
instead of less, than three-fifths as long as wing), ridged instead of 
rounded culmen, and less distinct lateral sulci of maxilla and mandi- 
ble. The coloration is very similar but Aphantochroa lacks the 
white tips to the lateral rectrices, so conspicuous in both sexes of 
both species of Phexochroa. The two groups are, however, very 
closely related, and Phxochroa undoubtedly is more nearly allied to 
Aphantochroa than to Campylopterus. 
KEY TO THE SPECIES AND SUBSPECIES OF PHZOCHROA. 
a. Basal half (approximately) of mandible pale brownish or whitish (reddish or 
pinkish in life); lateral rectrices extensively bronze-greenish basally. (Phxo- 
chroa cuvieri.) 
b. Green of under parts paler; abdomen paler, more buffy; bill slightly shorter. 
(Western Costa Rica to northern Colombia; coast of Venezuela?) 
Pheochroa cuvierii cuvierii (p. 363). 
bb. Green of under parts darker; abdomen darker and more brownish; bill slightly 
longer. (Coiba Island, Bay of Panamé4.) 
Phezochroa cuvierii saturatior (p. 365). 
aa. Mandible wholly dusky; lateral rectrices with little if any bronze-green on basal 
portion. (Guatemala and British Honduras to eastern Nicaragua.) 
Phzochroa roberti (p. 365). 
PHZOCHROA CUVIERII CUVIERII (Delatire and Bourcier). 
CUVIER’S HUMMING BIRD. 
Adults (sexes alike)—Above metallic bronze-green (sometimes 
more bronzy posteriorly), the tail usually more bluish or silvery green; 
lateral pair of rectrices extensively grayish white terminally (usually 
tinged on outer web with gray),* this separated from the bronze- 
greenish basal portion by an ill-defined band of dull blackish or 
- dusky, the second pair with a less extensive, but still conspicuous, 
whitish tip, the third sometimes slightly tipped with grayish; remiges 
dark brownish slate or dusky, faintly glossed with purplish; chin, 
throat, chest, and sides of breast rather dull metallic bronze or bronze- 
green, the feathers narrowly margined with dull grayish buffy or pale 
buffy grayish; flanks, abiaiien, and median line of breast pale 
isabella color or pale, dull brownish buffy, the first glossed with 
bronze or bronze-green; femoral tufts and tuft on each side of rump 
white, the latter usually intermixed with pale grayish; under tail- 
coverts dull metallic bronze or bronze-greenish, broadly margined 
with white; bill dull black, the basal half (more or less) of mandible 
pale brownish or whitish (fleshy or pinkish in life); iris dark brown, 
feet dusky. 
@ Sometimes there is a bronze-dusky spot at tip of outer web. 
