PASSERINE. TENUIROSTRES. 285 



ture ( T. Minimus) is no larger than a bee. A few, 

 however, are of comparatively large dimensions, the 

 largest of all being nearly equal in size to the com- 

 mon Swift (Hirundo Apus). They have a long and 

 very slender bill, enclosing a tongue usually described 

 as tubular, composed of two parallel filaments used 

 in sucking (or licking) the nectar from the tubes 

 of flowers. They eat minute insects also, which 

 they capture both on the wing, and within flowers ; 

 and it is probable that these, after all, form the prin- 

 cipal part of their nutrition. Their feet are very 

 small and slight, shewing that they perch but little, 

 but their excessively long and powerful, though nar- 

 row wings, their broad tail, and their largely de- 

 veloped breastbone (sternum), render them, perhaps, 

 the most perfectly aerial of all the feathered tribes. 

 " The flight of the Humming-bird is like that of 

 no other bird ; it has a character peculiarly its own. 

 When most birds fly, we perceive there is an evident 

 effort; that constant exertion, more or less, is ne- 

 cessary to support them in the air ; their tendency 

 appears to be to sink, which has to be constantly 

 resisted by muscular effort. The Swallows, and 

 some other tribes of swift and powerful flight, 

 appear to skim at will through any stratum of the 

 atmosphere without any tendency to rise or sink; 

 but the Humming-bird seems just like a cork drawn 

 under water ; he seems all buoyancy, as if his natural 

 place were above the clouds, and he had to struggle to 

 keep himself in the lower air ; he brings himself down 

 to suck the flowers, then shoots away with a springy 



