208 



NORTH AMERICAN BIRDS. 



short, iibout oqual to mirtdlo toe, with a continuous fi-ontal series of transverse scutellie; 

 claws extremely long and sharp, but weakly curved ; inner edge of the middle claw 

 slightly pectinated. Third to fourth quills longest ; outer five with inner webs sinuated. 



53081,f 



5308 l,f 



Rostrftannis Meirthilis. 



The species of this genus are two in number, and are peculiar to the 

 tropical portions of America, one of them being confined to the Amazon 

 region, the other extending to Florida in one direction and Buenos Avres on 

 the other. Their nearest allies are the species Circus and Elaniis, like 

 them inhabiting marshy localities, where their food is found, whicli consists, 

 in large part, of small mollusca. 



Species and Baces. 



Com:mon Ch.a.racters. Adult. Prevailing color plumljcous-black, or bluish- 

 ]ilniul5eous ; the tail and primaries black. Entirely concolored, or with wliite 

 tail-coverts. Cere and feet orange-red. Young. Spotted with blacki.sh-browu 

 and ochraeeous, the former prevailing above, the latter beneath. 



1. R. sociabilis. Tail-coverts, with terminal and basal zones of the tail, 

 white; that of the tail more or less shaded with grayish-brown. Adult. 

 Uniform blackish-plumbeous, darker on the bead, quills, and tail. Hab. 

 South America, West Indies!, and Florida. 



Plumbeous of a glaucous cast, the head dark plumbeous, and the 

 wing-coverts lighter, inclining to grayish-brown. Wing, 13.25 - lo..50; 

 tail, 6.75-8.25; bill, .85-1.04; tar.?us, 1.70-2.40; middle toe, 1.40- 

 1.55. (2 sp. P. A. N. S.) Hab. Florida and West Indies . var. plumbe us. 

 Plumbeous of a blackish cast, the head deep black, and the wing- 

 coverts not lighter, and not inclining to brownish. Wing, 12.90 - 14.00 ; 

 tail, 7.60 - 7.80 ; bill, .90 - 1.25 ; tarsus, 1.50 - 1.80 ; middle toe, 1.45 - 

 1.65. Hab. South America ...... var. so r /(/ 6 /?/.s.' 



' Eostrharmis sociabilin, var. sociahilis (Vir.iLL.). llerpcfolhercs .sociabUi.':, Vif.ii.t.. Nouv. Diet. 

 Hist. Nat. XVIII, 318, 1818 ; Enc, Metli. Ill, 1248. RostrJunniw! sociabiUs, D'Or.B. Voy. Am. 

 Merid. II. 73, 1835 ; SjTiop. Av. Mag. Zool. 1850. Or.w, List B. Brit. Mus. p. 47 ; Gen. 

 and Subgen. Brit. Mus. p. 6. — Kavi', Monog. Falc. Cont. Orn. 1850, 78. — Strickl. Oru. Syn. 

 I, 136, 1855. Falco rostrluimus. Max. Bcitiiig. III. 182, 1830. Cymindis Icucopygus, Spix, 

 Av. .Bras. I, 7, pi. ii, 1824. llostrhamvs niger. Less. Tr. Orn. p. 56, 1831. 



Hab. South and Middle America, from Buenos Ayres to Eastern Mexico (Mirador). 



Localities : Giiateniala (Sn.. Ibis, 1, 220) ; Ecuador (Sclater, 1860, 289) ; Panama (Law- 



