224 NATURAL HISTORY. 



Sub-tribe II. . . FISSIROSTRES DIURN.E. 



Family II Hirundimdae. (Lat. Hirundo, a Swallow. Swal- 

 low kind.) 



Sub-family a. . Cypselincc. 



CYPSELUS. (Gr. Kfyeho?, a Martin.) 



Apus (Gr. urrovc, without feet), the Swift. 



are firm and close, so as not to impede their passage through 

 the air ; their wing feathers are long, stiff and pointed, and 

 their tails are long and forked ; all which properties we know 

 to belong to great speed. 



The SWIFT, popularly called " Jack Screamer," is the largest 

 and swiftest of the British Hirundinidae. It seems to spend 

 the whole day on the wing, wheeling with wonderful velocity, 

 and occasionally soaring until it is hardly perceptible, but 

 screaming so shrilly that the sound is plainly heard. The 

 number of insects which it destroys is almost incredible ; 

 they are retained in a kind of pouch under the tongue, and 

 wiien taken out, could hardly be pressed into a tea-spoon. 



