BIEDS OF NORTH AND MIDDLE AMBKICA. 45 



nearly even, the back streaked with white and the rump with a 

 conspicuous patch of chestnut, cinnamon, or dull whitish. 



Bill verj"- short (exposed culmen shorter than distance from nostril 

 to eye), its width at posterior edge of nostrils about equal to length of 

 exposed culmen; culmen straight to near tip, where rather abruptly 

 decurved, but tip of maxilla very slightly uncinate; maxillary tomium 

 nearly straight, its subterminal notch minute. Tail less than half as 

 long as wing (shorter than distance from bend of wing to tip of longest 

 secondaries), nearly even, the slight emargination less than length of 

 exposed culmen. Tarsus shorter than middle toe (without claw), the 

 upper portion feathered for a considerable distance on inner side; 

 middle toe united to outer by about half the length of its basal 

 phalanx; claws of lateral toes reaching nearly or quite to base of 

 middle claw. 



Coloration."- — Adults with crown, back, and scapulars glossy blue- 

 black, the back more or less streaked with white; forehead white, pale 

 brown, or chestnut; rump chestnut, cinnamon, or cinnamon-buff; sides 

 of head chestnut or cinnamon; abdomen white; longer under tail- 

 coverts dusky, margined with whitish. - 



Nidification. — Nest retort-shaped, composed of mud-pellets, lined 

 with soft feathers, etc. , attached to rocks or sides (usually under eaves) 

 of buildings; eggs spotted. 



Range. — Temperate and tropical America, including Greater An- 

 tilles. One species in southern Africa. Indo-Malayan and Australian 

 regions ? 



The relationships of this genus are nearest to Hyloclielidon Gould, 

 and Lagenoplastes Gould, of Australia (the latter extending also to 

 India), which are similar in all respects to Petrochelidon except in the 

 tail, which is relatively a little longer and more deeply emarginated. 

 Both have the rump light colored (though the color is brownish white 

 or pale grayish brown instead of chestnut or cinnamon) and the back 

 streaked with white; but they have the under parts entirely whitish, 

 with narrow dusky streaks on the throat and chest, lack any rufous or 

 chestnut on sides of head, the type of Lageiwplastes having the entire 

 pileum rufous, that of JFIylochelidon being uniform blue-black. Lag- 

 enoplastes, at least, builds a nest identical in character with that of the 

 species of Petrochelidon. In short, the structural differences between 

 these two alleged genera (which I would unhesitatingly merge together) 

 and Petrochelidon are so slight that little violence would be done to 

 their relationship by referring them to the same genus.* 



« Of the American species, none of the Old World forms being seen by me. 



^ Their relationship to Petrochelidon is certainly very much closer than that exist- 

 ing between the American species hitherto referred to Hirundo and Atticora, 

 respectively. (See page 25. ) 



