FALCON [D.K- THK FALCONS. 



101 



Subgenera. 



One primary only witli iiinur wi'l. uumrgiiiiiicd ; lirst to sooonrl lonffost ; 

 first loiij;i'r than (biirtli. 



Tarsus lonffcr than niiilillc toe, and Icatheicil liir hi'low the knee ; (irst 

 ((Uill .shorter than third. Cohwation of the .sexes alil<e ; old and yoinnr 

 shjrhlly (lilVerent in pattern and tiiit.s. Size lar,w . . . nirrn/afrn. 



'"aisiis not lon-ei than njiddle toe, and .scarcely leathered below the 

 .ee; liist qnill ccpinl to or lonjrer than the thinl. Coloration of the 

 .sexes alike; old and yonnj,' very dillcrcnt in pattern and tint.s. Size, 

 very small to larfre .... r- 7 



Two primaries with inner webs emarginated ; second to third longest; 

 first shorter than Ibnrth. 



Basal joint of toes without transverse scutelUe; tarsus about equal to 

 middle toe. 



Coloration of the sera's in adult plumage very diflerent in 

 tints ; in the young alike, the young ^ resembling the adnlt 



9-. Size small j;,„!n,>. 



Ba.sal joint of toes with transverse scutelte; tarsus longer than mid- 

 dle toe. 



Coloration of the sexes very difieront, in pattern and tint.s, at all 

 ages; old and young alike. Scutella; of the toes and tarsus inter- 

 rupted at the digito-taisal joint ; tarsus unieh longer than middle 

 toe. Bill .small, the cere on top less than one fourth the culmen. 



S'^'^^'""" ri„nH„ndu.,. 



Coloration of the sexes alike at all ages; old and young .slightly 

 diflerent in pattern and tints. Seulelhc of tarsus and toes uninter- 

 rupted from '• knees " to claws ; tarsus but little longer than mid- 

 dle toe. Bill large, the cere on top about one third the culmen. 

 Size medium; form very slender Rluinchojakn. 



SuDGENu.s HIEROFALCO, Cuvieb. 



Uierofalco, Ctrvini!, 1817. (Type, Fako fjyr/a/co, Linn.) 

 Jerafako, BoiK, 1822 ; K.vui", 1851. (Saiuetyiic.) 

 Gcnnaia, Kavp, 18-17. (Type, Fako jiigrjcr, Gii.vv.) 



Species and Baces. 

 1. P. gyrfalco. Wing, 1.100 - 17.00 ; tail, 8.50 - 1 1.50 ; culmen, .85 - 1.05 ; tar.'^us, 2.10 - 

 3.00 J middle toe, 1.80 - 'J.25.' Gionnd-color vaiying from entirely pure white to wholly 

 dusky, but generally bluish (in adult) or gr.ayish-brown (in young) above, and white 

 beneath. Adull. Allthemarkingstransver.se.' No lighter nuchal band. Yuinirj. Mark- 

 ings of the lower surface longitudinal, the upper j.arts without transverse bars (except 

 on the tail'). ^ ^ 



a. Lower parts with white predominating, or wholly white. 



Lower tail-coverts never with markings. No tinge of blue anywhere on 

 the plumage, the ground-color of which is entirely pure white at all ages. 



* ICxtrcnies of .sixty speoiincns. 



• Sometimes there are more or le.ss distiuet linear streaks on the head and neck, or on the 

 pectoral region. 



" Sometimes the irregular markings above have a transverse tendency. 



