FALCONID^ — THE FALCONS. 209 



2. R. hamatus.' Tail-coverts, with end and base of the tail, slaty-black. 

 Adult. Uniform bluish-plumbeous, darker on the head, wings, and tail. Tail 

 uniform black, or with two narrow, interrupted, white bands across the mid- 

 dle portion {$, Brazil, B. S. Coll.). Wing, 11.00-12.00; tail, 5.00-7.00; 

 bin, 1.02-1.07; tarsus, 1.75- 1.90; middle toe, 1.45. Hob. Amazon region 

 of South America. 



Rostrhamus sociabilis, var. plumbeus, Eidgway. 



HOOK-BILL KITE; EVERGLADE KITE. 



Hostrhamus sociabilis, Vieill. D'Oke. Hist. Nat. Cuba, av. p. 15. — Cass. Birds N. Am. 

 1858, 38. — Maynakd, Birds Florida, Prospectus, 1872. 



Sp. Char. Adult male (No. 61,187, Everglades, Florida; C. J. Maynard). Prevailing 

 color plumbeous, becoming black on the secondaries, primaries, and tail, somewhat 

 brownish-ashy on the wing-coverts, and with a glaucous cast on the neck, the head 

 becoming nearly black anterioily. Tail-coverts (the longer of the upper and all of the 

 lower) and base of the tail pure white, this occupying more than the basal half of the 

 outer feather, and changing into grayish-brown next the black ; tail with a terminal band 

 of graj'ish-brown, about .75 wide. Inner webs of primaries marbled, anterior to their 

 emargination, Avith grayish and white. Tibite tinged with rusty fulvous. Wing-formula, 

 4, 3, 5 - 2 - 6 - 7, 1. Wing, 14.01 ; tail, 7.25 ; culmen, .95 ; tarsus, 1.90 ; middle toe, 1.55 ; 



REXCE, VII, 1861, 316) ; La Blata (Burmeister, II, 1861, 435) ; Brazil (Pelz. Orn. Bras. I, 

 6) ; Buenos Ayres (Scl. & Salv. 1869, 160). 



The numerous South American specimens which have come under my notice all differ in the 

 respects pointed out in the synopsis from West Indian and Floiidan examples. The following 

 descriptions of a pair of the southern race will show the average characters of var. sociabilis. 



Adult male ( Baranquilla, Ecuador, Crowther ; Coll. G. N. Lawrence). Differing from the 

 Florida male in being much darker ; general color plumbeous-hlack, instead of glaucous-plum- 

 beous ; head, wings, and tail deep black. Wing-formula, 3 = 4, 5-2, 6-7, 1. Wing, 12.90; 

 tail, 7.80 ; culmen, 1.05 ; tarsus, 1.65 ; middle toe, 1.45 ; hind toe, .80 ; its claw, 1.10. 



Adult female, with traces of immature plumage (53,081, Conchitas, Buenos Ayres, September, 

 1867 ; William H. Hudson). Whole plumage (except tail-coverts) brownish-black, deepest 

 black on head and tail ; more brownish on wing-coverts and slightly glaucous on the neck. All 

 the feathers, except those of the head, neck, and back, bordered inconspicuously with paler ; 

 these edgings more distinct and rufescent on the lesser wing-coverts ; tibiae tinged with rusty. 

 Wing-formula, 3=4, 5-2-6-7, 1. Wing, 14.00 ; tail, 7.60 ; culmen, 1.00 ; tarsus, 1.70 ; 

 middle toe, 1.60 ; hind toe, .95 ; its claw, 1.20. 



A specimen from Mexico, supposed to be from Mirador (No. 44,444), is dark in color, like 

 South American examples ; the bill is unusually large, the chord of the culmen measuring 1.25 ; 

 wing, 14.25 ; tail, 8.30 ; tarsus, 1.70 ; middle toe, 1.65. 



Specimens examined. — National Museum, 2 ; Philadelphia Academy, 7 ; New York Museum, 

 2; Cab. G. N. Lawrence, 2 ; Museum, Cambridge, 1 ; Boston Society, 3. Total, 17. 



1 Eostrhamus hcwiatus (Vieill.). Falco hamatus, Te.mm. PI. Col. 61, 231, I899. — Illig. 

 Mns. Berol. Bulco hamatus, Vieill. Enc. Meth. Ill, 1223. Eostrhavms tceniurus. Cab. J. fiir. 

 Orn. 1854, p. Ixxx. No. 16,634 (Amazon River ; Lieutenant Herndon). Entirely uniform plum- 

 beous, with a glaucous cast, becoming darker on the head, and black on primaries and tail ; tail 

 perfectly even, with an obscurely indicated, narrow, interrupted band of dark plumbeous across 

 its middle portion. A specimen in the collection of the Boston Society has the bands on the 

 tail more conspicuous, and agrees with the R. tceniurus of Cabanis. I have seen no young speci- 

 mens of this species, but, judging from Temminck's figure, cited above, they are very similar to 

 the same stage of A', sociabilis. 



VOL. III. 27 



