BIRDS OF NORTH AND MIDDLE AMERICA. 559 
aa, Bill much more slender, its depth at base equal to less than one-fifth the length of 
exposed culmen; tail much less than half as long as wing, slightly forked, the 
outermost rectrices little if any longer than middle pair, none of the rectrices 
distinctly acuminate; shafts of primaries and rectrices not distinctly (sometimes 
not at all) dusky. (Marquesas Islands, central Pacific Ocean.) 
Gygis microrhyncha (extralimital). a 
GYGIS ALBA CANDIDA (Gmelin)?> 
HAWAIIAN WHITE TERN? 
Adults (sexes alike) —Whole plumage immaculate pure white; 
shafts of primaries and rectrices brownish or dusky, and margin of 
eyelids black; bill black (in life “black at the tip, shading through 
purple to indigo blue at the base’’) ;° iris blue;? legs and feet “dark 
brown, the webs yellow.’ @ 
Immature.—Similar to adults, but with a postocular spot and 
anterior margin to eyelids black, and shafts of primaries and rectrices 
black or dusky. 
Young.—Similar to the immature plumage (as described above), 
but back, scapulars, and tertials tinged or washed with russet or 
brown, lesser wing coverts and middle rectrices margined terminally 
with brown or russet, shafts of primaries olive-brown, and shafts of 
(Fernando Noronha, Trinidad and Ascension islands); Sharpe, Journ. Linn. Soc., 
xx, 1890, 480 (Fernando Noronha); Ihering, Revista Mus. Paulista, iv, 1900, 294 
(descr. eggs.).—Gygis crawford: Nicoll, Bull. Brit. Orn. Club, xvi, no. cxxvi, July 10, 
1906, 102; Ibis, 1906, 669 (South Trinidad Island.) 
(2) Gygis alba monte.—Gygis alba monte Mathews, Birds Australia, ii, no. 4, Nov. 1, 
1912, 443 (Seychelles, breeding). 
(3) Gygis alba pacifica.—Sterna pacifica Lesson, Hist. Nat. Mam. et Ois., x, 1837, 
156 (Low Archipelago, Pacific Ocean).—Gygis alba pacifica Mathews, Birds Australia, 
ii, pt. 4, Nov. 1, 1912, 443 (Society Islands, Samoa, etc.).—Sterna nivea Bennett, 
Narrative Whaling Voy., i, 1840, 370 (Caroline Atoll). 
(4) Gygis alba royana.—Gygis alba royana Mathews, Birds Australia, ii, pt. 4, Nov. 
1, 1912, 433, 443 (Kermadec Island and Norfolk Island, breeding; Friendly Islands?). 
(5) Gygis alba kittlitziGygis alba kittlitzi Hartert, Katal. Vogelsamml. Senckenb. 
1891, 237 (Caroline Islands); Mathews, Birds Australia, ii, pt. 4, 1912, 443 (Caroline 
group; Mariannes?). 
(6) Gygis alba candida (Synonymy given separately.) 
4 Gygis microrhyncha Saunders, Proc. Zool. Soc. Lond., 1876, 668 and cut (Marquesas 
Islands, central Pacific Ocean; coll. Brit. Mus.); Cat. Birds Brit. Mus., xxv, 1896, 
152; Tristram, Ibis, 1881, 252; Cat. Coll. Birds, 1889, 10; Wiglesworth, Abh. Zool. 
Mus. Dresden, 1890-91 (1892), no. vi, 78; Kaiser, Journ. fiir Orn., 1902, 255 (Nauru 
Island). 
' ® Scantiness of material (I have seen no specimens at all from the American side of 
the Pacific) and the fragmentary manner in which the various forms are treated by 
the most recent reviser of the group, Mr. Gregory Mathews, necessitates the interro- 
gation mark in connection with the subspecific name. The Pacific-American. sub- 
species is referred tentatively to G. a. candida as being the nearest form geographically : 
but it may be different. 
¢ Gifford, Proc. Calif. Acad. Sci., 4th ser., ii, 1913, 32. 
7 Saunders, Cat. Birds Brit. Mus., xxv, 1896, 150. 
