A brief glance at the general form of a swallow's body h 
sufficient to indicate that it is essentially a creature of the air 
and indeed its insect food is captured on the wing. 
Swallows, of which a large number of species are known, 
are fownd all over the world. 
On account of a superficial resemblance tliey were at one 
time thought to be related to the swifts, but later research 
revealed important structural differences between the two 
groups. 
A lari^e number of the species are migratory and their 
breeding habits show considerable diversity. It will for in- 
stance be recalled that the common swallow and the house* 
martin of England make mud nests which are attached to 
houses whereas the sand-martin deposits its eggs at the end of 
a timnel which it digs in a bank. 
Very few species are found in the Malay Peninsula: the 
most interesting is perhaps Hirundo had'm, a handsome bird 
with the underparts entirely bright chestnut. It is restricted 
in range to the vicinity of limestone hills. 
