Plumbeous of a glaucous cast, the head dark plumbeous, and the wing-coverts lighter, inclining to grayish-brown. Wing, 13.25–15.50; tail, 6.75–8.25; 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. _plumbeus_. 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. _sociabilis_.[76] 2. =R. hamatus.=[77] 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 middle portion (♂, Brazil, B. S. Coll.). Wing, 11.00–12.00; tail, 5.00–7.00; bill, 1.02–1.07; tarsus, 1.75–1.90; middle toe, 1.45. _Hab._ Amazon region of South America. Rostrhamus sociabilis, var. plumbeus, RIDGWAY. HOOK-BILL KITE; EVERGLADE KITE. _Rostrhamus sociabilis_, VIEILL. D’ORB. Hist. Nat. Cuba, av. p. 15.—CASS. Birds N. Am. 1858, 38.—MAYNARD, 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 anteriorly. 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 grayish-brown, about .75 wide. Inner webs of primaries marbled, anterior to their emargination, with grayish and white. Tibiæ 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; hind claw, 1.10, the toe, .90. Bill deep black; cere and naked lore bright orange-red; feet deep orange-red.