BIBDS OF HOKTH AND MIDDLE AMERICA. 129 



with bright green and yellow, rarely with blue on head; usually plain 

 olive, olive-green, or gray above (sometimes relieved by whitish or 

 yellowish wing-bars), and plain whitish or yellowish beneath. 



Nidification. —Nest (so far as known) suspended from a forked 

 branch, composed of fine vegetable fibers, mosses, lichens, etc. ; eggs 

 white, usually more or less spotted. 



Range'. — Temperate and tropical America, except Galapagos Archi- 

 pelago. 



The Vireos (sometimes called Greenlets) are active arboreal birds, 

 mainly insectivorous though feeding also on fruits and berries. As a 

 rule they are fair songsters, although some species are distinguished 

 for the oddity rather than melody of their notes. So far as known 

 they all build pensile nests, and lay white eggs with a few dark specks. 



The familj^ is peculiar to America, but chiefly tropical, and is repre- 

 sented by about seventy known species, referable to eight genera. 



KEY TO THE CENBKA OV VIREONID^. 



u. Lateral toes relatively shorter, the inner toe (without claw) shorter than the 

 hallux (without claw), its claw not reaching beyond base of middle claw. 

 h. Bill more slender, relatively less deep and compressed, its depth at frontal 

 antipe not greater than its width at same point; sides of maxilla without 

 grooves. 

 c Tail slightly rounded, even, or emarginate; throat and chest not slate-gray. 

 d. Tenth primary rudimentary and concealed or else very small and narrow, 

 less than one-third as long as ninth ; the latter longer than fourth ; wing- 

 tip longer than commissure, or else the latter longer than tarsus, 

 e. Bill relatively longer and more slender, its depth at frontal antite not 

 greater (usually much less) than half the distance from nostril to tip 

 of maxilla, the latter measurement at least equal to length of gonys; if 

 the tenth primary obvious the ninth shorter than fifth; wing without 



whitish bars or other markings Vireosylva (p. 130) 



ee. Bill relatively shorter and stouter, its depth at frontal antite equal to 

 much more than half the distance from nostril to tip of maxilla, the 

 latter measurement decidedly less than length of gonys; if the tenth 

 primary obvious the ninth longer than sixth; wing with two conspicu- 

 ous white bars Lanivireo (p. 161 ) 



Ad. Tenth primary well developed, more than one-third (frequently one-half) 

 as long as ninth, the latter shorter than fourth (sometimes shorter than 

 first or, rarely, shorter even than secondaries); wmg-tip shorter than 



commissure, the latter shorter than tarsus Vireo (p. 176) 



cfl. Tail much rounded; throat and chest slate-gray Neochloe (p. 211) 



hh. . Bill stouter, relatively deeper and more compressed, its depth at frontal antise 

 decidedly greater than its width at same point; sides of maxilla with fine 



longitudinal grooves « Laletes (p. 212) 



aa. Lateral toes relatively longer, the inner toe (without claw) as long as or longer 



than hallux (without claw), its claw reaching decidedly beyond base of 



middle claw. 



6. Bill smaller and more slender, the culmen slightly decurved terminally; smaller 



(wing less than 65 mm.) Paohysylvia (p. 214) 



«This feature may not be constant, only one specimen having been examined. 

 10384— VOL 3—03 ^9 



