38 FIELD KEY TO THE LAND BIRDS. 
SWALLOWS. — Mirundinidae. 
Bini. — Very small, with a large, cleft 
( & mouth. 
FEET. — Small. 
Foon. — Insects caught on the wing. 
These birds are generally seen on the wing, spar- 
ingly perching. They migrate south in the winter, 
some species going as far as Southern Brazil. 
93. PURPLE MARTIN. Progne subis. — 
Length, 8 inches. Glossy blue-black. Female and 
young black above; brownish gray below; belly 
white. The Martin builds its nest on houses and 
barns, or in boxes hung in trees. 
94. CLIFF OR EAVE SWALLOW. Petro- 
chelidon lunifrons. — Length, 6 inches. Steel blue 
above; forehead white; side of head chestnut; a 
gray-brown ring around the neck ; breast gray-brown ; 
belly white; upper tail coverts red-brown. Builds 
under overhanging rocks, or the eaves of barns, 
basket-like nests made of mud. 
95. BARNSWALLOW. Chelidon erythrogaster. 
—Length, 7 inches. Forehead and throat red-chest- 
nut; upper parts steel-blue black; underparts white ; 
