520 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
Proc. Calif. Acad. Sci., 4th ser., ii, pt. 1, 1913, 19 (Crossman, Culpepper, and 
Wenman islands, Galapagos; habits; Clipperton Island and Oneal Rock, near 
Socorro Island). 
S[terna] fuliginosa Rorasosiip and Hartert, Novit. Zool., vi, 1899, 204 (Wenman 
and Culpepper islands). 
Haliplana fuliginosa var. crissalis LAWRENCE, Proc. Bost. Soc. N. H., xiv, 1871 
(pub. 1872), 285 (Socorro Island, Revillagigedo group, w. Mexico; coll. 
U.S. Nat. Mus.; ex Baird, manuscript); Mem. Bost. Soc. N. H., ii, 1874, 318 
(Socorro; Tres Marias). 
Sterna fuliginosa crissalis Nutson, N. Am. Fauna, no. 14, 1899, 24 (Tres Marias 
Islands; Isabella Island; habits; crit.).—Bamzy (H. H.), Auk, xxiii, 1906, 
378 (Isabella Island, w. Mexico, breeding). 
Sterna fuscata crissalis AMERICAN ORNITHOLOGISTS’ UNION ComurrTEE, Auk, xxv, 
July, 1908, 345. 
[Sterna] crissalis Saarpr, Hand-list, i, 1899, 136. 
Genus STERNULA Boie. 
Sternula Bors, Isis, x, 1822, 563. (Type, by monotypy, Sterna minuta Lin- 
neus=S. albifrons Pallas.) 
Very small Sternide (wing not more than 185 mm., usually con- 
siderably less), with gonys much longer than mandibular rami; tail 
only about half as long as wing, with lateral rectrices slender and 
acuminate terminally, and tarsus not longer than middle toe with 
claw. 
Bill about as long as head, rather slender, with gonys decidedly 
longer than mandibular rami and with basal angle rather prominent; 
latero-frontal antia nearer (in vertical line) to mental than to malar 
antia. Wing long and pointed, the longest primary (outermost) 
exceeding distal secondaries by more than twice the distance from 
tips of the latter to bend of wing. Tail about half as long as wing, 
forked for less than half its length, the lateral rectrices slender and 
acuminate, or subacuminate, terminally. Tarsus slightly shorter 
than middle toe with claw; webs with anterior margin slightly or 
moderately incised. 
Plumage and coloration.—Occipital feathers normal (soft and 
blended), Adults of most species with forehead and under parts 
white (the latter sometimes gray), the rest of pileum (sometimes 
whole pileum) and a loral streak black; back, wings, etc., pale gray. 
Downy young buffy or buffy-whitish above, sometimes nearly im- 
maculate, but always (?) with more or less numerous irregular 
markings of dusky. 
Range.—Nearly cosmopolitan. (About eight species, three of 
them American.) 
KEY TO THE AMERICAN SPECIES AND SUBSPECIES OF STERNULA. 
a. Under parts white (or at most very faintly tinged with gray); tail pale gray. 
6. Smaller (wing less—usually much less—than 180 mm.); bill usually tipped 
with blackish; black loral streak broader; color of back, etc., paler gray. 
(Sternula antillarum.) 
