142 NORTH AMERICAN BIRDS. 



is boldly blotched with markings of a bright chestnut-brown, varying greatly 

 in its shadings. 



Subgenus iESALON, Kaup. 



u^salon, Kaup, 1829. (Type, Faico (xsalon, Gmelix, = F. lithofalco, Gm.) 

 Hypotriorchis, Auct. ncc Boie, 1826, the tj'pe of which is Falco subbuteo, LiNN. 

 Dendrofalco, Gray, 1840. (Type, F. cesalon, Gmel. ) 



This subgenus contains, apparently, but the single species F. lithofalco, 

 which is found nearly throughout the Northern Hemisphere, and in different 

 climatic regions is modified into geographical races. Of these, North Amer- 

 ica possesses three, and Europe one ; they may be distinguished as fol- 

 lows : — 



Species and. Races. 



F. lithofalco. Second ami third quills longest; first usually shorter than, 

 occasionally equal to, or rarely longer than, the fourth. Adult female, and young 

 of both sexes. Above brownish, var3nng from pale earth-brown, or umber, to 

 neai-ly black, plain, or with obscure transverse spotting of lighter ; tail with five 

 to eight lighter bands, which, however, are sometimes obsolete, except the tei-- 

 minal one. Beneath ochraceous-white, longitudinally sti'iped Avith brown or 

 dusky over the whole surface. Adult male (except in var. suckleyi and richard- 

 soni?). Above plumbeou.s-blue, with darker shaft-streaks; tail with more or 

 'less distinct bands of black, and paler tip. Beneath much as in the female and 

 young, but stripes usually narrower and more reddish. Wing, 7.20 - 9.00 ; tail, 

 4.90 - 6.30 ; culmen, .45 - .60 ; tarsus, 1.30 - 1.60 ; middle toe, 1.15 - 1.51. 



a. Adult male plumbeous-blue above; sexes very unlike in adult dress. 

 Female and young without transverse spotting on upper parts. 



Adidt male. Tail deep plumbeous, tipped with ash, with six transverse 

 series of dusky spots (which do not to .ch the shaft nor edge of the 

 feather.s) anterior to the subterminal zone, the black of which extends 

 forward along the edge of the feather. Inner web of the longest 

 primary with ten transverse spots of white. Streaks on the cheeks 

 enlarged and blended, forming a conspicuous " mustache." Pectoral 

 markings linear black. The ochraceous wash deepest across the nape 

 and breast, and along the sides, and very pale on the tibial. Adult 

 female. Above brownish-plumbeous, the feathers becoming paler 

 toward their margins, and with conspicuous black shaft-streaks. Tail 

 with eight (three concealed) narrow bands of pale fulvous-ashy ; longest 

 primary with ten light spots on inner web. Outer webs of primaries 

 with a few spots of ochraceous. Young. Similar to the 9 "dult, but 

 with a more rusty cast to the plumage, and with more or less distinct 

 transverse spots of paler on the upper parts. Wing, 7.60 - 9.00 ; tail, 

 5.10-6.30; culmen, .45-. 55; tarsus, 1.35-1.47 ; middle toe, 1.15-1.35. 

 Hab. Europe var. lithofalco.^ 



1 Falco {^salon) lithofalco, var. lithofalco (Gmelin). Accipiter lithofalco, Briss. Orn. I, 1760, 

 349. Falco lithofalco, Gmel. S. N. 1789, 278. .Fsalon lithofalco, Kaup. Ueb. Falk. Mus. 

 Senck. 258. Falco regulus, Gmel. S. N. 1798, 285. Accipiter a;salo7i, Briss. Orn. I, 1760, 382. 

 Falco a^salon, Gmelin, S. N. 1789, 284. — Yarrell, Hist. Brit. B., ed. 1871, 74. Hypo- 

 triorchis msalon. Gray, Gen. 1844, Sp. 10. Falco intermixtus, Daud. Tr. Orn. II, 1800, 141. 



