BIRDS OF NORTH AND MIDDLE AMERICA. 553 
KEY TO THE SPECIES AND SUBSPECIES OF MEGALOPTERUS.2 
a. Lores light gray to grayish white, like pileum; general coloration lighter. 
b. Islands of western Indian Ocean (Seychelles, Mauritius, Madagascar, etc.)—. 
Megalopterus tenuirostris tenuirostris (extralimital).? 
bb. West coast of Australia ....Megalopterus tenuirostris melanops (extralimital). 
aa. Lores black or very dark brown, in strong and abrupt contrast with gray or white 
pileum; general coloration darker. 
b. Whole forehead (as well as crown, etc.) distinctly white or gray, sharply defined 
against black of lores; lores black, much darker than cheeks. (Megalopterus 
minutus.) 
c. Pileum white or grayish white, in rather abrupt contrast with deep gray of 
hindneck; gray of tail much darker. 
d. Color of under parts, hindneck, and upper back slightly darker. (West 
Indies, Gulf and Caribbean coasts of Mexico and Central America, etc.). 
Megalopterus minutus atlanticus (p. 554). 
dd, Color of under parts, hindneck, and upper back slightly lighter and grayer. 
(Philippine Islands.)....Megalopterus minutus worcesteri (extralimital).¢ 
a Specimens of Megalopterus are so few in American collections (with the exception of 
M. melanogenys and M. diamesus) that I am unable to bring together a sufficient series 
to show clearly the relationships of the several forms. Therefore, this ‘‘key”’ is a 
provisional one only. Besides the forms here mentioned, Mr. Gregory Mathews, the 
latest reviser of the group, in his Birds of Australia, recognizes the following sub- 
species, but I have not seen specimens of any of them, nor of M. tenuirostris tenui- 
rostris and M. diamesus: 
Megalopterus tenuirostris melanops.—Anous melanops Gould, Proc. Zool. Soc. Lond., 
1845 (pub. Feb., 1846), 103 (Houtman’s Abrolhos, w. coast Australia); Birds Australia, 
vii, 1848, pl. 35 and text; Handb. Birds Australia, ii, 1865, 417.— Megalopterus tenui- 
rostris melanops Mathews, Birds Austraha, ii, pt. 4, Nov. 1, 1912, 414, 416.—Sterna 
tenuirostris (not of Temminck) Schlegel, Mus. Pays-Bas, Sternae, 1863, 37 (Australia) — 
Anous tenuirostris Saunders, Proc. Zool. Soc. Lond., 1876, 670, part (monogr.); Stone, 
Proc. Ac. Nat. Sci. Phila., 1894, 117, part (West Australia; crit.) —Micranous tenui- 
rostris Saunders, Cat. Birds Brit. Mus, xxv, 1896, 144, part (West Australia}.— 
(?)Anous atrofuscus Stone, Proc. Ac. Nat. Sci. Phila., 1894, 117 ‘‘ (Mer de Monte- 
video ’’).—(?)A[nous] atrofuscus Ridgway, Man. N. Am. Birds, 2d ed., 1896, 48, part. 
Not having seen either form of this species I am unable to give their distinctive 
characters. 
Megalopterus minutus marcusi—Micranous marcusi Bryan, Occ. Papers Bernice 
Pauahi Bishop Mus., ii, 1903, 101 (Marcus Island).—Megalopterus minutus marcust 
Mathews, Birds Australia, ii, pt. 4, Nov. 1, 1912, 423 (Marcus Island; Mariannes?). 
b Sterna tenutrostris Temminck, Pl. Col., 1823, pl. 202 and text (‘‘Senegal’’); Schlegel, 
Mus. Pays-Bas, vi, no. 24 (Sternae), 1864, 37, part (Reunion; Mauritius) — Megalop- 
terus tenutrostris Gray, List Gen. Birds, 1840, 79.—Hydrocecropis tenuirostris Boie, 
Isis, 1844, 179.—Anous tenuirostris Reichenbach, Natatores, 1848, pl. 20, fig. 288; 
Saunders, Proc. Zool. Soc. Lond., 1876, 670, part, pl. 61, fig. 1 (monogr.); Hartlaub, 
Fauna Madagasc., 1861, 86; Vég. Madagasc., 1877, 392; Milne-Edwards and Grandidier, 
Nat. Hist. Madagasc., Ois., 1882, pls. 290a, 2900 (osteology); Stone, Proc. Ac. Nat. Sci. 
Phila., 1894, 115-117, part (Mauritius; crit.).— AMJicranous tenuirostris Mathews, Birds 
Australia, ii, 1912, pl. (116) facing p. 414.—Megalopterus tenutrostris tenuirostris 
Mathews, Birds Australia, ii, pt. 4, Nov. 1, 1912, 416 (Seychelles, breeding). 
¢ Micranous worcestert McGregor, Philippine Journ. Sci., Sec. D, vol. vi, 1911, 185 
(Cavalli, Sulu Sea).— Megalopterus minutus worcestert Mathews, Birds Australia, ii, 
no. 4, Nov. 1, 1912, 423 (Philippines). 
