1865.] GENERA AND SPECIES OF CYPSELIDZ. 611, 
portions of the brick to which it was fastened to give way sooner 
than the cement with which it had been secured.”—N. Am. Ool. i. 
p. 109. 
7. CHA&TURA VAUXII. 
Cypselus vauxii, Towns. Journ. Acad. Philad. viil. p. 148. 
Acanthylis vauxii, Bp. Compt. Rend. xxxviii. p. 660, Notes s. les 
coll. de Delattre, p. 90, et Consp. p. 64; Cass. Ill. B. Cal. i. p. 250. 
- Chetura vausit, Baird, B. N. Am. p. 145; Sclat. Cat. Am. B. 
p- 282, et P. Z. S. 1863, p. 100. 
Chetura ?, Sclat. et Salv. Ibis, 1860, p. 37. 
Fuliginosa ; dorso et capite eneo tinctis; urepygio pailidiore ; 
gutture albo; ventre obscure fuliginoso, gulam versus sensim 
dilutiore: long. tota 4°3, ale 4°7, caude 1°5. 
Hab. Western North America, from British Columbia south 
through Mexico to Guatemala. 
Mus. P. L. S. 
Readily distinguishable from C. pelasgia by its smaller size, paler 
rump, nearly white throat, and lighter underparts. C. poliura, 
which somewhat resembles it, is blacker on the back and head, and 
much darker below. 
8. CHZ2TURA POLIURA. 
~ Cypselus poliourus, Temm. Tabl. Méth. p. 78 (ex Buff. Pl. Enl. 
726. f. 2. 
Acanthylis cinereicauda, Cass. Proc. Acad. Philad. 1850, p. 58. 
Cypselus pelasgius, Max. Beitr. iii. p. 347. 
Acanthylis oxyura, Burm. Syst. Ueb. ii. p. 366. 
Acanthylis polioura, Bp. Consp. p. 64. 
Chetura poliura, Sclater, Cat. Am. B. p. 283, et P. Z. 8. 1863; 
p. 101. 
Acanthylis brachyura, Jard. Ann. N. H.ser.1. xviii. p.120 (1846)? 
Supra eneo-nigra; uropygio et tectr. caude sup. fuliginosis ; 
subtus fuliginosa, gutture albicantiore : long. tota 4:2, ale 4'8, 
caude 1°8. 
Hab. Cayenne ( Buff.) ; Tobago (Kirk). 
Mus. P. L. 8. 
One of the specimens of this species in my collection is said to be 
from Brazil; but the other is certainly from Cayenne, and Buffon 
describes the species as from that country. I have compared my 
examples with the type of Mr. Cassin’s A. cinereicauda in the Phi- 
ladelphian collection, and with type specimens of M. Temminck’s 
C. poliurus in the Leyden Museum, and find them all identical. A 
specimen of Mr. Kirk’s from Tobago, obligingly presented to me by 
Sir William Jardine, and typical of his A. brachyura, does not seem 
to be decidedly different, although the tail is rather shorter and the 
upper coverts are much produced, so as to reach nearly to the end 
of the rectrices. It is, however, possible that this form may prove 
distinct on comparison of a suite of specimens. 
