HIRUNDINID53. 
397 
a single foreign species, which feeds by night 
in the manner of the Caprimulgidce ; and in 
both groups completely insectivorous do we find 
species at times feeding on fruits and berries, 
the whole running into each other in a manner 
beautifully graduated, at the same time each 
being distinct and easily separated. The Swal- 
lows range over the whole world, and are every 
where migrating birds. They breed in the cre- 
vices of rocks, or form curious nests of various 
substances agglutinated together by their saliva, 
and most delight in the vicinity of waters. The 
colours of the plumage are steel blue, glossy 
green, and brown, contrasted with white and 
chestnut. In Britain we have two genera. The 
first of which is 
Hirundo, Linn . — Generic characters . — Bill 
small, very slightly bent, triangular, dilated at 
the base, rictus very ample, without bristles ; 
feet incessorial, but very slender ; tarsus 
short ; wings long, pointed, first quill longest ; 
tail forked, often much developed. 
Types. — II. rustica, urhica, riparia. 
Note. — Colours of the plumage glossy blue or 
green, varied by chestnut and white ; migra- 
tory, mostly gregarious. Cosmopolite. 
