932 SPOLIA ZEYLANICA. 
There are three Indian sub-orders: Cypseli, Swifts ; 
Cauprimulgi, Nightjars; and Podargi, Frogmouths. Each 
sub-order consists of a single family. 
Sub-order CYPSELI. 
Family CypsELip 2%. 
Swifts. 
Outwardly Swifts resemble Swallows, in each case the form 
having been specialized for the purpose of a swift and enduring 
flight. Anatomically there are considerable differences. In 
the structure of the sternum, feet, and wings, the Swifts are 
Picarian, while the Swallows are typically Passerine. All 
Swifts have ten tail feathers, Swallows have twelve. The 
primary wing quills are very long and curved, the secondaries 
extremely short. The bill is small and hooked at the tip, 
while the gape is broad. The hind toe is either directed 
forwards or is more or less reversible. Swifts are aerial in 
their habits, and feed entirely upon insects captured on the 
wing. They are found all over the world, except in Arctic 
or Antarctic regions. Their powers of flight are enormous, 
and they often cover immense distances in the course of a day’s 
wanderings. All our species are resident or mainly so. The 
nidification varies, but all species lay white eggs, and in almost 
all cases the materials of the nest are cemented together with 
hardened saliva, which is also used to glue the nest itself to the 
surface from which it depends. 
The family is divided into three sub-families :— 
(1) Cypseline.—The true Swifts, in which the tarsus is 
feathered, and all the front toes have but three phalanges or 
joints. 
(2) Cheturine.—Spinetails, &c., have the normal number 
of phalanges in the three front toes, 7.c., three in the second 
toe, four in the third, and five in the fourth. In most forms, 
including both our Ceylon species, the tarsus is naked. 
(3) Macropterygine.—Crested Swifts differ from the two 
preceding sub-families, in that the closed wings only just 
reach the end of the tail instead of extending far beyond it, 
while the head is crested. 

