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1 



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iTS 



REVIEW or AMERICAN UIIIDS. 



,r>-»; Jtl. • 



[part I. 



lower mandible falling within its otiord. NnstrilH superior, broadly op«n, ami 

 nearly oiruuiar, without any adjacent membrane, the «dged rounded. Legi 

 Htout. TarHUij equal to middle too without ulnw ; the joint feathered ; lateral 

 ttieu about <*iiual ; the basal Joint of the middle toe half free internally, ruther 

 leHd DO externally. Clawa strong, muoh curved 



The preccdinf^ diagnosis is infonded to characterize two groups 

 of Swullovvs, dilTcriiig ospeciully from all others in their thickciu'd 

 form, r(»l>UHtness of bill and feet, and especially in the elonguted, 

 comparatively powerful hill, the uj)per jaw (let;urved, its comniibKunil 

 edge much sinuatcd from the bas<', instead of &a in all the otlitrs— 

 Wing nearly straight to near the tip — so that a line from angle of 

 month to tip will include the whole lower jaw. With these chanirters 

 iu common, there are two well-marked subgenera, recognizable as 

 follows : — 



Pboone. Plumage glossy black above. Tail deeply forked, the lateral feathers 

 much and gradually pointed. Bill most robust; upper outline convex 

 from base. Tarsus with a few feathers only at base, on inner face. 



Ph^opuoone. Plumage dull mouse brown above. Tail emarginate, or Imt 

 slightly forked ; the lateral feathers very abruptly pointed, and rounded. 

 Bill weaker and more deprest»ed ; uppnr outline straight to near the tip. 

 Tarsus with a line of feathers along inner edge for two-thirds the length 

 from base. 



H MAI 



Ih '! 



,#■' 



'Es 



a. Progne, Boie, 



Bill notched, robust, and deep ; the commissure ranch sinnated, convex, and 

 ascending to the nostrils, then concave to the tip. Maxilla convex above from 

 base ; lower mandible slightly convex below, mnoh more so above. Frontal 

 feathers with a few bristles at base ; none appreciable in chin. The upper 

 joint of tarsus covered with feathers slightly adherent along inner face above, 

 but not extending along the groove. Scutellse distinct. Lateral toes about 

 equal, reaching to base of middle claw ; all the clawfi very strong, and mnili 

 curved. Tail much forked ; the feathers much pointed ; the wings pointed, 

 reaching beyond tip of tail. Plumage compact ; glossy black above, with 

 purple, violet, or blue reflection. Below either similarly colored, or with 

 \rhite belly and crissum. 



I have found it very difficult to come to any definite conclusion in 

 reference to the species of Progne inhabiting the continent of Ame- 

 rica, or to determine with accuracy their geographical distribution, 

 notwithstanding the large number of specimens examined, including 

 those in the Phila. Acad, of Xat. Sciences. This is due, in great 

 measure, to the variation of plumage with age and se.x — the young 

 birds of one species representing the adult plumage of another — aud 





