VIREONID^ — THE VIREOS. 357 



Family VIREONID^. — The Vireos. 



The essential features of this family appear to consist in the combination 

 of the dentirostral bill, notched in both mandibles ; the ten primaries (except 

 Vireosylvia), of which the outer is usually from one fourth to one half the 

 second ; the rather short, nearly even tail, with narrow feathers, and the 

 great amount of adhesion of the anterior toes, — the whole basal joint of 

 the middle being generally united on both sides to the adjacent joints, and 

 decidedly shorter than the basal of inner or two basal of outer. The outer 

 lateral toe is generally appreciably longer than the inner, reaching con- 

 siderably beyond the base of the middle claw. The tarsi are always dis- 

 tinctly scutellate anteriorly. The young are never spotted, or streaked as 

 in the Thrushes ; nor, indeed, do the adults exhibit such markings. 



The Virconidce are peculiar to the ISTew World, and are widely distributed, 

 although but one genus belongs to the United States. 



Genus VIREO, Vieill. 

 Vireo, Vieill. Ois. Am. Sept. I, 1807, 83. (Type, Muscicapa noveboracensis, Gm.) 



No great violence will be done by considering all the American Vireos as 

 belonging to one genus, divisible into three subgenera, as, however different 

 the extremes of the series may be from each other, the gradation is quite 

 complete. 



The North American species take a wide range during their southern 

 winter migration, only paralleled in this respect by the Sylvicolidce ; they do 

 not visit the West Indies, save as very rare stragglers to Cuba ( V. olivaceus, 

 solitarius,fiavifrons, and noveboracensis). They all have a melodious song, and, 

 so far as known, make a deep nest, suspended by its upper edge between the 

 forks of a horizontal twig. The eggs are white, generally with a few reddish 

 or brown blotches. 



Quite a number are characterized by leaving the eyes white, red, or 

 yellow. 



Subgenera. 



Vireosylvia. Bill compressed, narrow ; culmen and commissure straight, 

 the tip abruptly curved (or, if this is not the case, there is no trace of light 

 bands on the wing ; see section " b "). Superciliary stripe continued back to 

 the occiput. No trace of light bands on the wing. No conspicuous ring round 

 the eye. 



a. No spurious primary. Bill compressed, its tip abruptl}' hooked ; culmen 

 and commissure straight. Crown decidedly more ashy than the back. 



Sp. flavoviridis, barbatulus, olivaceus, jJhUndeJjjJiicus. 



b. An acute spurious primary. Bill depressed, the tip only slightly hooked ; 

 culmen slightly curved. Crown scarcely more ashy than back . . Sp. gilvus. 



