HUMMING-BIRDS. 6 



the Swifts, with which they have many points of their internal 

 organization in common. Even their long slender bills, which 

 appear so very different from the wide-gaping mouth of a Swift, 

 are much less so at an early period of their life. Mr. Wallace 

 describes the nestlings of some species of Humming-bird ; they 

 had the bill short and broadened, the gape wide, and, in fact, 



The " Sword-bill " Humming-bird feeding on the tubular flowers of Brugman&ia. 

 (One fourth nat. size.) 



more resembling that of a Swift than that of the adult parent bird. 

 The bill of Humming-birds, although always very slender, is very 

 variable in shape and size, being straight in some and curved in 

 others ; in some extremely short, as in the Thorn-bills {Rampho- 

 micron), and in others extremely long, as in the Sword-bill 



