458 NORTH AMERICAN BIRDS. 



&. Upper parts plain graj'ish 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- 

 hano-ino; scale. 

 6'. Tail forked for much more than length of tarsus. 



&. Tail forked for about half its total length, the outer pair of feathers 

 abruptly narrow^ed 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.) 

 &. 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.) 

 ¥. Tail forked for less than length of tarsus. 



c\ No feathers on hind part of tarsus ; entirely white beneath, the adults 



brightly colored above 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.) 



Genus PROGNE Boie. (Page 457, pi. CXIV., fig. 1.) 



Species. 



Common Characters. — Adult males wath 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 w^hite. 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\ Adidt 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 pai'ts dull light grayish, or graj'ish 

 white (centres of feathers darker); sides and flanks similar, but darker; 

 belly and under tail-coverts white. 

 h^. Larger, with bi'oader tail-feathers. Adult tnale with feathers of ventral re- 

 gion entirelj^ 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, tair3.00-3.40 (forked'for .70-.90). Nest in holes 

 of trees or about houses, in boxes, etc. Eggs 3-5, .97 X -72, plain j^ure 



