G 
EEArTIFUL BIEDS. 
the air, and the rapidity with which they are worked, 
cause that humming sound from whence, as we have 
said, their name is derived. 
The tail assumes a great variety of shapes, but the 
feathers are of the same firm character as those of the 
wings. It is pointed, rounded, squared, forked, very 
broad, ample, or scanty, in accordance no doubt with 
some peculiarity in the habits or economy of each 
species. 
One of the most remarkable characters in these 
birds is observed in the bill. Its general form is long 
and slender, nearly of an equal thickness throughout, 
vdth the exception of the tip, which is usually very 
sharp and keen ; but it varies considerably in length 
and ciuwature ; 
and in some of 
the species its 
insectiverous 
character is 
developed more 
strongly by the 
presence of re- 
curved saw-like teeth on the edges of the mandibles 
towards the point, as in Trocliilus recurvirostris, and 
some others. In nearly all the species the upper 
mandible overlaps, or partially sheathes, the under 
one. Although in some of these characters the Hum- 
ming Birds may partially resemble the Swift, how 
totally different is the form of the instrument by 
which their food is taken. Both birds seize their 
tiny prey while upon the wing ; the latter gaping wide 
to snatch it, and passing onward in its rapid flight ; the 
