482 BIRDS OF n.Ln<oi8. 



anec of tliosc. howpvcr. oi\ m'conJiirli'h; rump riitln.'ly blackiHli hrowii; upper tall- 

 coverts wholly wlilto. Tall hoary sliite. Imwil tUlrJ (or mon.O white, the junction o( the 

 two eolorn Irregular and broken: tip obseuroly puler: feathers obscurely lilueki^h alonii 

 edues. and with obKolele tranHverse spots of tin- wime; white prevalllni; on Inner wel>«. 

 Benealli entirely imri' while seareely variegated: tibia' and tan*! with a few sealt<'red 

 Bniall transverse spots of blackish: flunks with larsur. more cordate spots of the same. 

 (Breeds In this plumaeo.) 



This magnificent hawk, which Dr. Cones justly styles the "hand- 

 somest of the North American Falconiihe," is perhaps little more 

 than a stra<,'glcr to Illinois. It has heen seen by the writer only in 

 the far West, where the few obserAed were sailing majestically over- 

 head, describing broad circles, and resembling the flolden Eagle in 

 the manner of their Hight. At such times it may be immediately 

 distinguished from .1. sancii-johdiuih by the snow^ white of its 

 lower plumage, which, as seen from below, is the predominating 

 color of the bird. 



Geni s AQUILiA Brisson. 



Aqiiila UiiiSH. Orn. i, 17G0. 119. Type (by elimination), Fnlvo r It ni union Linn. 



Gen. Chab. Form robust and structuro powerful: benrinB and Boneral aspect of 

 Biileu and Arrhihiiteo. WiiiK Iouk, tile primaries lone and strond, with their emarclnn- 

 tions very deep. Tail rallier short, sliKhtly rounded or wedue-sluiped. Bill stroneer 

 than in the preeedinc scnera, its outlines nearly parallel, and the tip somewhat inclined 

 backward at the point; commissure with a more or less prominent festoon: nostril nar- 

 rowly oval, vertical: skin of the cere very hard and (Inn. Supc^rciliary shield very prom- 

 inent. Feet very stronc. the membrane between (he outer and middle toes very much 

 developed: tarsus less than twice as long as the middle toe; outer toe equal to, or longer 

 than the inner; claws very long and strong, very much graduated in size; scutelln- of 

 the toes small except on tile terminal joint, where they form broad transverse plates; 

 tjirsi densely feathered all round down to the base of the toes: tibial plumes well devel- 

 oped, loose-webbed, their ends reaching down to or beyond the base of the toes. 

 Feathers of hind neck and occiput lanceolate, acute, and distinct, forming a "cape" of 

 ililTercntly formeii feathers. Third to fifth iiuill longest ; (Irst shorter than the seventh; 

 outer live or six with their inner webs deeply emarginated. 



This genus is almost peculiar to the Olil World, where about 

 seventeen so-called species are known, while America has no mem- 

 ber of the genus exclusively its own, the single North American 

 species being the same as the European one. Though the details 

 of external structure vary somewhat, ;nul the size ranges from that 

 of Biilco liitlxnimtis to that of a sea-eagle (IliiUtrciiis), the generic 

 characters given in the above chagnosis apply equally well to all 

 the species. 



