328 ' FALCONIDJE. 



Rostliramua niger, Less. Traite, p. 66 (1831). 



EostLramus ham.atus, Gray, Gen. B. i. p. 25 (1845) ; Bp. Consp. i. 



p. 20 (1850) ; Cub. in Schomb. Eeis. Ginan. iii. p. 73G (1848). 

 Rosthramus sociabilis, Strickl. Orn. Syn. p. 136 (1855) ; Scl. 8f Sain. 



Nomencl. p. 121 (] 873). 

 Ibycter sociabilis, 8chl. Mas. P.-B. Polybori, p. 7 (1862) ; id. Revue, 



p. 138 (1873). 



Adult. Entirely bluish slate-colour, the head, neck, and uuder- 

 parts rather inclining to leaden grey ; secondaries as well as pri- 

 maries and their coverts blackish, with a very slight gloss of greenish; 

 tail grey, Avith a broad terminal band of black ; cere, lores, angle of 

 mouth, and bare part of lower mandible intense orange-yellow ; iris 

 blood-red. Total length 13-5 inches, culmen 1-8, wing 11-7, tail 

 5-5, tarsus 2, middle toe 1-35. (J/hs. Lugd.) 



Young male. Very similar to that of R. leueopygus, and having 

 the base of tail-feathers and upper tail-coverts whitish, and the tips 

 of the tail ashy brown. It is smaller, however, than that species : 

 wing 12-5 inches, tail 6-8, tarsus 1-8. {Mus. Liigd.) 



A young female in the Leiden Museum had the wing 12, tail 6-1, 

 tarsus 1'9. 



Hah. Eastern Brazil northwards to Guiana. 



2. Rosthramus taeniurus. 



Rosthramus tajuim-us. Cab. J. f. O. 1854, p. Ixxx ; Scl. S,- Salv. 

 Nomencl. p. 121 (1873). 



Similar to R. sociabilis, having a dark rump, with a white base 

 to the tail and three bands across the latter, two basal and one 

 median. Total length 15 inches, culmen 1-85, wing 11'6, tail 6*6, 

 tarsus 1-95. {3£us. Bcrol.) 



Hab. Para. 



I regret that when in BerHn I did not more fully describe the 

 type, from which, however, the measurements are taken. I fancied 

 at the time that it was not distinct from one of the other two 

 species ; but I have not been able to reconcile it with either of them. 

 The species of Rosthramus are not well known, and their characters 

 and geographical distribution still require working out with a good 

 series. 



3. Rosthramus leueopygus. 



Cymindis leueopygus, Spix, Av. Bras. i. p. 7, pi. 2 (1824). 

 Rosthramus sociabilis, UOrb. Voi/. Amer. 3Ierid., Ois. p. 73 (1847) ; 



Cass. B. Calif. 8f Texas, p. 107 (1855) ; id. in Baird, B. N. Am. 



p. 38 (1860) ;■ Gray, Hand-l. B. i. p. 27 (1869) ; Coues, Key N. Am. 



B. p. 211 (1872) ; Maynard, B. Florida, pi. 1 (1872). 

 Rosthramus hamatus, Burm. Th. Bras. ii. p. 46 (1856) ; id. La Plata 



Reise, ii. p. 435 (1861) ; Leot. Ois. Trinid. p. 31 (1866) ; Pelz. Orn. 



Bras. pp. 6, 398 (1871). 

 Ibycter leueopygus, ScM. 3Ius. P.-B. Polybori, p. 8 (1862) ; id. Revue, 



p. 138 (1873). 

 Rosthramus leueopygus, Scl. 8f Salv. Nomencl. p. 121 (1873). 



Adult. Entirely slaty black, with a slight brownish shade on the 

 wings and scapulars ; upper and under tail-coverts and base of tail 



