THE SWIFT. 



317 



at other seasons they skim the earth and play for hours together over 

 the surface of the water, in chase of the gnats that emerge in myriads 

 from the streams. The gape of the mouth is therefore exceedingly 

 great in these hirds, reaching as far as a point below the eyes. The 

 bill itself is very short, flattened, pointed, slightly curved downward, 

 and broad at the base. 



The group which is scientifically termed the Hirundinidse is a very 

 Jarge one, and is divided into two lesser groups, the members of one 

 being classed together under the title of Swifts, while the others are 

 known by the name of Swallows. With the former birds we have first 

 to deal. 



The Sw^iFTS are readily distinguished from the Swallows by the very 

 great comparative length of the first two primary feathers of the wing, 

 which are either equal to each other or have the second feather longer 

 than the first. The secondaries are remarkably small, being nearly 

 concealed under the coverts. There are ten primaries in the wing, and 

 the same number of quill feathers in the tail. 



The Swift {Cypselus apus). 



The true S>vifts — of which England aflTords two examples, one very 

 familiarly known, and the other a very rare and almost unnoticed spe- 

 cies — are remarkable for the feathered tarsus, the long wings, and the 

 peculiar form of the feet. In this member all the toes are directed 

 forward — a structure which is admirably adapted to the purpose which 

 it fulfils. The Swifts build their nests— or rather lay their eggs, for 

 the nest is hardly worthy of the name — in holes under the eaves of 



