FALCOXID.E — THE FALC()N8. 323 



1. H. pelagicus.' W'ms, 2-i.')0 -•20.00; tail, 1:5.50 - 10.00; culmcn, 

 2. flit: iKiiih (if liill, 1.80; ueiv, on top, 1.10; taivsus, 3..")0 ; micldlL' too, 

 2.!».'). Adult. Foii'licad, iriuatiT \viiii;-cov<.'i'ts, abdonit'ii, and tail, white; 

 otluT pdilioiis l)l,icki.-iii-l)i'i)\VM (.VrcT.). Yoiiiiij. Daik unibci' or black- 

 ish-lii'o\vn, llio I'catlicrs of ihc licad and nec-k willi liijliter .■^liaft-stix'aks; 

 tiTtials (cxt.'i'pt at ends) and lia.<al lliird, or uiorc, of inner webs oC tail- 

 Ibaliiec-, white; tail-eovert.s mucK nii.xed wilii the saniL'. Ilith, North- 

 iMstern Asia. , 



B. Tail of Iwelve leather.-J, only .';lii,ditly roundeii. Lower end of tlie nostril 

 roinided, openin;; more alirnpliy inward; upper outline of the cere nearly 

 straight; lores seantily featliered. 



2. H. albicilla. Winj;, 2;3.(HI--JS.OO; tail, 1 l.oO- 10.00 ; enlmen, 2.0.5 - 

 2.2(1; laisiis, ;!.;!() -li.SO; middle toe, 2.o(l - 2.0.") ; depth of bill about 

 1.4.") ; cere, on top, .8.>. Adult. Head and neck pale j^rayish-fulvou.s, 

 or dirty yellowisli-iri'ay, not abruptly li^diter than the body. Tail, 

 only, pine white. Itest of the plnma;;e, including,' the tail-eoverts, 

 dark fjraj'ish-brown, inclining to blackish on the primaries. Yoiunj. 

 Prevailing tint of the upper parts light isabclla-color, or pale grayish- 

 cinnamon, each feather having a terminal triangular spot of blacki.sh- 

 brov, n. Ilrcast soiled white, wilji broad stripes of brownish-black; 

 rest of the lower parts lu'arl}' uniform fulvous-brown, the tibiiu darker. 

 Ilith. Europe; Egypt; (ireenland. 



3. H. leucocephalus. Wing. 20.00-20.00; tail, 10.")0- 1.').50 ; cul- 

 nien, 1.8.")- 2.2(1; tarsus, 2.O.") - ii.VO ; middle toe, 2,3.") - 3.10 ; depth 

 of bill about 1.30; cere, on the top, .80. Adult. Head and neck, 

 tail and tail-coverts, pure v.hite, immaculate (except in transition 

 dress). Rest of the plmnagc brownish-black. Yoiiiuj. Brownish-black, 

 .showing miK'l'. concealed while at the bases of the fe.ithers; ground- 

 color inclining to umbcr-browu on the upper surface; on the lower 

 parts, the b.asal white much exposed and predominating, the blackish 

 forming longitudinal, tear-shaped spots. Head and neck brownish- 

 blaek, the penieillated feathers of tlie nape seldom wi'h whitish points. 

 Tail-feathers and primaries black, the inner webs usually more or less 

 marked, longitudinally, with bufly-whitish. Iluh. The whole of North 

 America. 



.Si'. CiiAi!. Kofoi.v ./(•mft/c(?) (28,100, Amoor River ; Mr. Burlingamc). Form: very similar 

 to //. albkiUti and //. hucocrphala, but bill altogctlii'r luorc robust, and feet rather less so, than 

 in these. Tail, of fourtecu I'eutiicrs ! grtiduated for about one half its length. Dimensions : 

 About the size of the female of the two other species, t'olor : nenerally dusky vandyke-browii, 

 a medial line on the lanceolate feathers of the neek, and the border of the sipiaiiiate ones of the 

 tibiie, deei.lcdiy lighter. Kntire plumage white at the lia.se, this exposed wherever the feathers 

 are disarranged, and iirevailiiig on the (•rissuni. Tertials, basal half of inner webs of primaries, 

 the wholi- tail, and iijiiier tail-eoverts, white with a yellnwish tinge. Tertials, ui)per tail-coverts, 

 and tail-feathers, with a large terminal spot of clear giayish-blaek ; on the tail these form a rather 

 irregular teniuiial zone, being on the middle feather narrower, and broken into fine blotches. 

 IJill, cere, lore, and feet, yellow ; end of upper mandible, and the claws, black. Wing-formula, 

 3, 4, 2, 5-G-7 = 1. Wing, 21.r.0 ; tail, 13.50 ; culuieu, 2.G0 ; depth of bill, 1.80 ; cere, on 

 top, 1.10 ; tarsus, 3.50 ; middle toe, 2.95. 



