FAMILY VIREONID^. VIREOS. 



271 



FAMILY VIREONID^. 



Vireos. 



Upper mandible, with very small hook at tip ; first primary, very short 

 in some species, in others nearly as long as second ; toes, joined at base. 

 Plain colored birds, usually greenish or grayish, but often showing a faint 

 wash of yellow on underparts ; tail, always without white spots. 



Group 1. Wing, less than 2.37 inches long. 



Crown, grayish ; orbital ring and lores, dull white. Rarely occurs east of 

 Illinois. 



Bell's Vireo. 



Vireo bellii. 

 See No. 480. 



Crown, grayish, often tinged with olive; orbital ring and lores, 

 yellow. 



Wliite=eyed Vireo. 



Vireo noveboraceiisis, and races. 

 See No. 478. 



