CYPSELUS. 291 
fortunate enough to receive a generic name which they were able to 
retain, Illiger having rechristened the genus under the appellation of 
Cypselus in his ‘Prodromus systematis Mammalium et Avium, p. 229. 
He designated the Common Swift, the Hirundo apus of Linneus, as the 
type. 
The true Swifts are characterized by having the tarsus feathered to the 
base of the toes, which are all directed forward. The prevailing colour of 
the Swifts is a brownish black, in some species variegated with white. 
The similarity in the pattern of colour between the Swifts and the 
Swallows is very remarkable; in both families the sharply defined white 
rump and dark pectoral band are occasionally met with. 
Sclater, in his monograph of the Cypselide (Proc. Zool. Soc. 1865, 
p. 593), enumerates fifteen species belonging to this genus, most of which 
breed in the southern portions of the Palearctic Region, and in the 
Ethiopian and Oriental Regions. One species visits Australia in winter, 
and four others are confined to the Neotropical Region. Two species only 
occur in Europe, one of which is a regular summer visitor to the British 
Islands, and the other is a rare accidental visitor. 
The Swifts live almost entirely on the wing, rarely perching in trees or 
on the ground, and consequently frequent open country. They feed 
exclusively on insects, and are therefore unable to remain in any locality 
where the winter is at all severe. They breed in holes of various kinds, 
the crevices of rocks, crannies in buildings, hollow trees, or the recesses 
of palm-foliage. The nest is very slight ; the materials are made to adhere 
to each other by the glutinous saliva of the birds. Their eggs are few in 
number, elongated and blunt in shape, and unspotted dull white in 
colour. 
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