BIRDS OF NORTH AND MIDDLE AMERICA. 69 



basal phalanx, to the inner by about half its basal phalanx; claws of 

 lateral toes scarcely reaching to base of middle claw. 



Coloi^ation. — Upper parts and under tail-coverts glossy blue-black; 

 under parts (except tail-coverts) white, with a black patch on each 

 side of breast and another (partly concealed) in center of breast. 



Nidijication. — Nest in holes of trees and buildings, composed of fine 

 grasses, feathers, etc. ; eggs immaculate white. 



Range. — Costa Rica to Patagonia. (Monotypic %") 



KEY TO THE SPECIES (OR SUBSPECIES ?) OF PYGOCHELIDON. 



a. All the under tail-coverts black; feathers of upper back with concealed spots of 

 white or very pale gray; smaller (adult male averaging wing 96.2, tail 50.9, tar- 

 sus 10, middle toe 9.1; adult female, wing 94.6, tail 50.8, tarsus 10.1, middle toe 

 9.2). (Costa Rica to southern Brazil and northern Chile.) 



Pygochelidon cyanoleuca (p. 69) 

 aa. Only the longer under tail-coverts black, the shorter (anterior) ones white, like 

 abdomen, etc. ; feathers of upper back with concealed spots of gray but not of 

 white; larger (adult male averaging wing 98.8, tail 52.5, tarsus 11.2, middle 

 toe 9.7; adult female, wing 101.4, tail 54, tarsus 11.7, middle toe 10.6). (Chile, 

 Patagonia, Uruguay, and Argentina. )..Pygochelidon patagonica (extralimital)^ 



PYGOCHELIDON CYANOLEUCA (Vieillot). 

 BLTJE-ANB-WIUTE SWALLOW. 



Adults {sexes alike). — Above glossy, dark violaceous steel blue, this 

 color also extending over sides of head and neck to extreme lateral 

 portion of chest, but the auricular region sometimes lusterless black, 

 like lores;, lesser and middle wing-coverts black, broadly margined 

 with dark violaceous steel blue; greater coverts similar, but with bluish 

 margins much less distinct; remiges and rectrices grayish black; under 

 tail-coverts black, broadly margined with dark steel bluish; under 

 wing-coverts and axillars dark sooty gray, the marginal coverts more 

 or less distinctlv tipped with whitish; rest of under parts white, 

 strongly shaded with gra3dsh brown (sometimes mixed with glossy 

 blue-black) on sides and flanks; centei of chest with a more or less 

 distinct cluster of dusky spots, these sometimes forming an interrupted 

 narrow collar across chest, sometimes (though very rarely) almost 

 wanting; feathers of upper back spotted beneath surface with Avhite 

 or very pale grayish; bill black; iris brown; legs and feet light horn 

 brownish. 



"Possibly two species, it being doubtful whether P. patagonica (D'Orbigny and 

 Lafresnaye) is a species or subspecies, though for the present, not having seen evi- 

 tlence or indication of intergradation, I prefer to accord it .specific rank. 



^> I[[irund<)'\ ]>a(ag(mica D'Orbigny and Lafresnaye, INIag. de Zool., 1837 (Synopsis 

 Avium, p. 69) (Patagonia). — Atticora patagonica Baird, Review Am. Birds, 1865, .'511, 

 footnote. — Atticora hemlpijga Burmeister, Reise La Plata, ii, 1861, 479 (Mendoza, 

 Argentina). — Atticora cyanoleuca (not Hinnido c//anoto(m Vieillot) Sharpe, Cat. Birds 

 Brit. Mus., X, 1885, 186, 634, part; Sharpe and Wyatt, Men. Hirund., 1894, 605, part. 



