208 



NORTH AMERICAN BIRDS. 



siidrt, about erinnl tn inidillc tnc, witli a continuous frontal scries of transverse scntcllre; 

 claws cxtroiiR'ly lonir and sliarp, hut weaidy curved; inner edge of the middle elaw 

 sliyhtly peetinaled. Tiiird to fourth quills longest ; outer five with inner webs sinuated. 



53081,? 



^f"^ 



53081,^ 



Roftrhaviiis xnrifihilin. 



53081,:^. 



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

 tro])ical portions of America, one of thera being- confined to tlie Amazon 

 region, tlie other extending to Florida in one direction and Buenos Ayres on 

 tlie otlier. Tlieir nearest allies are the si>ecies Clrcits and Elanus, like 

 tliem inliabiting marshy localities, where their food is found, whicli consists, 

 in large part, of small mollusca. 



Species and Baces. 



Common Ciiahacters. AduU. Prevailing color plumbeous-black, or bluish- 

 phnnbeous ; the tail and primaries black. Entirely eoncolored, or with white 

 tail-coverts. Cere and feet oi'ange-red. Young. Spotted with blackish-brown 

 and ochraceons, the former prevailing abov(!, the latter beneath. 



1. R. Bociabilis. Tail-covert.s, with terminal and basal zones of the tail, 

 white; that of tiie tail inoie or less shaded with grayish-brown. Adult. 

 Uniform blackish-phimljeous, darker on the head, quills, and tail. Hah. 

 South America, West Indies, and Florida. 



riumbeous of a glaucous car-t, the head dark plumbeous, and the 

 wing-coverts lighter, inclining to grayish-brown. Wing, i;3.25 - lo.'jO ; 

 tail, 6.75 -8.2o; bill, .85- 1.04 ; tarsus, 1.70-2.40; middle toe, 1.40- 

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

 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, 7.00 - 7.80 ; bill, .90 - 1.25 ; tarsus, 1.50-1.80; middle toe, 1.45- 

 1.05. Hab. South America var. .loci ah His. ^ 



1 Hn.'i/rliamus socinblll.i, var. .sorinlnlis (ViElLL.). Herpffothcrns sociabilis, Xiv.iu.. Nonv. Diet. 

 Hist. Nat. XVIII, 318, 1S18 ; Eiic. Mikh. HI, 1248. Jlostrhamus .lociabUi.i, D'Oim. Voy. Am. 

 Merid. II. 73, 1835 ; Syiio]). Av. JIag. Zoiil. IB.IO. Oiiay, List H. lirit. Mus. p. 47 ; Ocii. 

 and Suligcn. Hrit. Mus. p. (i. — Kaii-, Monog. Falo. font. Orn. 1850, 78. — SriticKi.. Orn. Syn. 

 I, Ki'i, 185.'). Fii/fo mKlrhaiiiux, Max. ndti-iig. III. 182, 1830. Ci/mindi.i hucopi/giis, Simx, 

 Av. Ihas. I, 7, pi. ii, 1824. Itoslrhamns ni<ier, Lkss. Tr. Orn. ji. 56, 1831. 



Had. South and Middle Anicriia, from Hiicnos Ayres to KiistiMii Mexico (Mirador). 



Localitius : Guatemala (Sei,. Ibis, I, 220) ; Ecuador (SoLAtKlt, 1800, 289) ; Panania (Law- 



