FALCDN I U.K — THE FALCONS. 



149 



.«pot.'<, thwo most conspicuous on tlie wiiijrs ami si.'ii|mi1iiis, Sui.'onilario.s crossed with 

 tiii'co liiuiils (iC (lcc]ici', nioiv r('(lilisli uclinicuous. ISiUiils ot'llii' tail puic while, [n oilier 

 respects exactly as in the male. Wiiijj-l'onnula, .'!, 'J ~ I - 1. Win;:, l).(l(); tail, (i.lO; 

 ciilineii, .')"); taisMs, 1.4(1; middle toe, 1.51. 



Yoiiii;/ male ( Kl.51(l, Fort Hice, Daeotali, July 20, 1805; l!ii,i(.-(icn. Allied Sully. T. S. A., 

 S. M. ItnlhamiMi'f). Dill'crini.' I'nim iIk; adult only in niitmie details. Tppcr sm-liice with the 

 rnsly holders of the leathers iiuiii' washed over the ;,'eiieial .-iiilace; the riisty-oehraeeoii.s 

 fornis the i.'roiiiid-colnr oC the head, — paler antpriorly. where the black sliall-.strenks are 

 very cuiispieiiDiis ; s[iots on the pi iiiiaiy coverts and primaries dc'cp reddish- ochraceoiis ; 

 tail-hands liioader than in the- adult, and more redilisii ; the terminal one twice as lnoad 

 as the rest (.40 of an inidi), and almost creain-color in tint. IJciicath pale ochrncooiis, 

 tlii.s deepest on the breast and sides; markings as in the adult, but (i.'ial region and lower 

 tail-coverts immaculate; the sliall-streaks on the tibite, also, .scarcely disi.<'rnible. Wing, 

 7.00; tail, 4.(iO. 



1 1 An. Interior regions of North America, bctwceu tho Mississippi Valley and the 

 PiDcky Mountains, from Texas to the Arctic regions. 



usr 'If ai'iici.MiiNS k.^aminkh. 

 National Museum, 10 ; Museum Conip. Zool., 2 ; 11. Ridgway, .3. Total, 15. 



Meusureiiieiiti. 



Since originally duscribiiig this bird, I have s'"in additional e.Xiiinple.s, and 

 still con.sider it as an easily recoynized race, not at ail ditliciilt to distinguish 

 i'roMx col II nihil riifs. Xow, however, I incline strongly to the theory that it 

 represents merely the light form oi" the central prairie regions, of the common 

 s])ecies ; since its cliarticters seem to be so analogous to these of the races 

 of L'ntci) horealia and BiiJw i-uyiniunns of the same country. It is doul)tfiil 

 whether some very ligi it-colored adult males, supposed to belong to coliim- 

 bariiis, as restricted, should not in reality be referred to this rtice, as the 

 adult plumage of the male. But having seen no adult males from the region 

 inliabited by the ])resent bird obtained in tlie breeding-.season, I am still in 

 doubt wliether the [Jiesent form ever tissumos the blue ])lumage. 



As regards tiie climatic or regional modifications exi)erienced by the 

 Falco UtIiuJ'ak'o on tlie American continent, the following summary of i'acts 

 expresses my present views upon tiie subject. First: e.Xiimples identical in 

 all respects, or iit least i)resenting no variations beyond those of tin individual 

 cliaracter, may be fotuid from very widely separated localities ; l)ut the 

 theory of e.xjdanation is, that individuals of one race may become scattered 

 during their migrations, or wander oil' from tiieir breeding-places. Second : 

 tiie Atliuitic region, tlie region of the plains, iind the region of tlie north- 

 west coast, have eiuili ti jieculiar nice, characterized by features wliich tire 

 also distinctive of races of otiier birds of tlie same region, namely, very 

 dark — the dark tints intensified, and their area extended — in the north- 



