458 NORTH AMERICAN BIRDS. 
ce. Upper parts plain grayish brown; lower parts similar, but lighter, be- 
coming white on belly; edge of outer quill roughened with stiff, 
recurved hooked tips to the barbs... Stelgidopteryx. (Page 463.) 
a, Nostrils opening laterally, and bordered above by a broad membrane, or over- 
hanging scale. 
b'. Tail forked for much more than length of tarsus. 
c. Tail forked for about half its total length, the outer pair of feathers 
abruptly narrowed for terminal portion, and inner webs of all (ex- 
cept middle pair) marked with a large whitish spot; lower parts 
cinnamon or buffy, the throat darker, more rusty. 
Chelidon. (Page 460.) 
ce. Tail forked for much less than half its total length, the outer pair of 
feathers not abruptly narrowed terminally; inner webs of tail- 
feathers without white spots; lower parts entirely pure white. 
Callichelidon. (Page 462.) 
b*%. Tail forked for less than length of tarsus. 
c. No feathers on hind part of tarsus; entirely white beneath, the adults 
brightly colored above.......csseeceeeesees Tachycineta. (Page 461.) 
c. A small tuft of feathers on lower portion of tarsus, behind; lower 
parts white, interrupted by a broad band of grayish brown across 
chest ; upper parts grayish brown..........+. Clivicola, (Page 462.) 
Gznus PROGNE Bors. (Page 457, pl. CXIV., fig. 1.) 
Species. 
Common Cuaractrrs.—Adult males with upper parts uniform glossy blue-black 
or dark steel-blue (sometimes inclining to violet); lower parts similar to upper 
surface, or with belly white and elsewhere glossy blue-black, or with anterior por- 
tions grayish, the posterior white. Adult females with upper parts plain glossy 
blue-black (sometimes interrupted by a grayish collar), the lower parts dull gray- 
ish anteriorly and white posteriorly. Young: Similar to adult female (the male 
two years, or more, in attaining the full plumage). 
a, Adult males with lower parts wholly glossy blue-black, like the upper; adult 
females with steel-blue of upper parts duller and less continuous, usually 
broken by more or less distinct grayish borders to feathers, the forehead and 
hind-neck dull grayish; anterior lower parts dull light grayish, or grayish 
white (centres of feathers darker); sides and flanks similar, but darker; 
belly and under tail-coverts white. 
b. Larger, with broader tail-feathers. Adult male with feathers of ventral re- 
gion entirely sooty grayish beneath surface. Adult females and immature 
males with anterior and lateral lower parts pale gray, the feathers, espe- 
cially on chest, with distinctly darker (sooty grayish) centres. Length 
7.25-8.50, wing 5.65-6.20, tail 3.00-3.40 (forked for .70-.90). Vest in holes 
of trees or about houses, in boxes, ete. Hyggs 3-5, .97 x .72, plain pure 
