132 INSECTIVORI. CYPSELUS. SwirFt. 
blackish-brown. Throat, belly, and upper tail coverts, 
white. Tail brown, forked. Tarsi and toes naked, 
with the exception of a few small feathers placed at 
the insertion of the hind toe. The Female similar in 
plumage to the Male bird. ; 
The Young have the upper parts of their plumage bor- 
dered with pale or wood-brown; and the tail-feathers 
margined with yellowish-white. 
Genus XX. SWIFT. CYPSELUS, Ilig. 
GENERIC CHARACTERS. 
Bill very short, depressed, and wide at the base, triangu- 
lar ; the gape extending beyond the posterior angle of the 
eye; upper mandible deflected at the pomt. Nostrils cleft 
longitudinally on each side of the ridge, open, with a promi- 
nent margin, beset with small feathers. Feet, having the 
tarsi very short and thick; toes four, all directed forwards, 
entirely divided, of two phalanges each, strong, and armed 
with thick and hooked claws. ‘Tail composed of ten fea- 
thers. Wings very long, the first quill being rather shorter 
than the second. 
Dr Lartuam, in his Index Ornithologicus, (under the 
head Hirundo Apus) first suggested the propriety of sepa- 
rating the Swifts from the Swallows. In this idea he is sup- 
ported by Innicer, TEmminckx, and other eminent natural- ~ 
ists, who have accordingly adopted the generic term Cypselus 
for these birds. In many respects they resemble the prece- 
ding genus, feeding and living much in the same manner. 
They construct their nests in the holes of buildings, or in the 
clefts of rocks, forming them of various soft materials, col- 
lected upon the wing, cemented together by a viscid matter, 
secreted probably for that purpose, by appropriate glands. 
They never alight upon the ground; the shortness of their 
legs, compared with their great length of wing, preventing 
their rise from a flat surface. 
