156 BIRDS CF INDIA. 



like the Swifts, have a tendency to revert the posterior toe. Their 

 plumage is dense, soft, and glossy. 



Swallows are found in every quarter of the globe. Some extend 

 their migrations over whole continents; a few are exceedingly local. 

 Some build their nest? on rocks or buildings, usually of mud, which 

 they consolidate with their saliva, and which in some are open 

 at the top, in other closed, and with a tubular entrance. In a few 

 cases the nests are made of grass, leaves, hair, and feathers ; and one 

 species, according to Gould, makes no nest whatever, but deposits 

 her eggs in the holes of trees. Others nestle in holes in trees, 

 and some in holes in river banks, generally lining the nest copiously 

 with feathers. Their chief diet is insects captured in the air, though 

 some of the American Swallows are said to live much on berries. 

 Many of the Swallows have a pleasing twittering song, which they 

 utter both Avhen seated and occasionally on the wing. 



The Ilinindinince have tlieir general anatomy much as in other 

 Insessores, the sternum larger, the keel more developed, and the 

 fissures smaller. Some are described as having, like the Swifts, large 

 salivary glands, with the saliva of which they agglutinate the mud 

 used in making their nests. Their intestinal canal is short and wide. 

 Several genera have been instituted for the birds of this family, 

 but without any strongly marked characteristics of structure. 



Gen. HiRUNDO, L. (as restricted), true Swallows. 



Syn. Cecropis Boie (part.) 



Char. — Bill rather large, very broad at the base, triangular, com- 

 pressed at the tip ; tail long and forked, or short and square, or 

 sub-furcate; tarsus naked ; feet moderate. 



The true Swallows are variously classified by different authors. 

 Bonaparte arranges them in two groups : — 1st, Ilirundo, with the 

 whole upper parts synchromous, and living in the open country ; 

 2nd, Cecropis, with the head, or rump, or both, more or less rufous, and 

 often streaked below. I shall here follow this arrangement. 'J'he 

 hind claw of this group is said to be stronger than in the last. 

 Blyth* groups them according to the kind of nest they build, and 

 this brings them together very much as above. 



♦ Monograph of Indian Hirundinidte. 



