93 
NORTH AMERICAN BIRDS. 
Tail very deeply forked, much longer than closed wings ; lateral 
feathers linear and very narrow at end, twice the length of central. 
Upper parts and pectoral collar steel-blue ; front and throat, some- 
times under parts, rufous. Tail-feathers with large spots. (Page 
•33.) . * . . . . . . . Hdrundo. 
Tail with shallow fork, not exceeding half an inch, shorter than 
closed wings. Feathers broad. Color blue or green above, with 
or without white rump; white beneath. Tail-feathers without 
spots. (Page 33.) . . . . . . . Tachycineta. 
Tarsus with a tuft of feathers at lower end. Lateral claws lengthened, 
reaching beyond base of middle claw. 
Tail slightly forked. Color dull-brown above; beneath white, 
with brown pectoral collar. (Page 34.) ..... Cotyle . 
b. Tarsus long ; equal to middle toe and half claw ; entirely bare. Tail con- 
siderably forked, about equal to closed wing. Color green above; white 
beneath. Hob . Bahamas, Jamaica ...... Callichelidon . 
Genus FROGNR, Boie. (Page 31.) 
F. subis. Above lustrous blue-black; beneath lustrous blue-black or brown- 
ish-gray, uniform, or with the abdomen and crissum white, or w r hitish. Females 
always with the throat and jugulum gray. Length, about 7.50. Nest in hollow 
trees or boxes. Eggs white. 
A. Adult males entirely steel-blue. Females and young males with the abdo- 
men pure white. 
Feathers about the anus smoky -gray beneath the surface. 
Wing about 6.00 ; fork of tail, .80 deep. $ and Juv. Abdominal and 
crissal feathers always with dusky shafts, and with the concealed por- 
tion grayish. Forehead and nape hoary grayish. Hab. Continental 
North America, except arctic regions Bermuda. {Purple Martin.} var. sub is. 
A Feathers about the anus snowy-white beneath the surface . 
Wing, 5.50 ; fork of tail, .90 deep. and juv. Abdominal and cris- 
sal feathers entirely snowy-white, — never with dusky shafts (except 
$ juv. in transition). Forehead dusky grayish-brown; nape steel- 
blue. Hab. Cuba and Florida Keys. ( Cuban Martin.) var. eryptoleuca . 
Genus FRTROCHELXDON, Cabanis. (Page 31.) 
Above glossy bluish-black, the back with concealed streaks of white ; head and neck, 
except on cap, and including nuehal collar, rump (and crissum faintly) chestnut-brown. 
Beneath dull white, tinged with reddish-gray on sides. Nest of mud, lined, built against 
rocks, or under eaves of houses. Originally with cylindrical bottler-shaped entrance. Eggs 
white, spotted with reddish. 
Frontlet reddish-white, with narrow band of black along upper mandible. 
Length, 5.15. Hab. United States; south to Panama. Not found in West In- 
dies. {Cliff Swallow .) ......... var. lunifr ons . 
Frontlet chestnut-brown, without black at base of upper mandible. Length, 
4.50. Hab. Mexico and Guatemala. {Mexican Swallow.) . . var. swainsoni . 
