458 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
Family STERNIDE. 
THE TERNS. 
=Sternine Bonaparte, Geog. and Comp. List Birds Europe and N. Am. 1838, 61; 
—LAWRENCE, in Baird, Rep. Pacific R. R. Surv., ix, 1858, 837, 858.—Carus. 
Handb. Zool., i, 1868, 362.—Coves, Proc. Ac. Nat. Sci. Phila., 1869, 214, 
Key, 1872, 317; 2d ed., 1884, 734, 754.—ScuaTer and Savin, Nom. Av. 
Neotr., 1873, 147.Barrp, Brewer, and Ripeway, Water Birds N. Am., 
ii, 1884, 196, 197.—SaunpErs, Cat. Birds Brit. Mus., xxv, 1896, xiii, 3, 4.— 
AMERICAN ORNITHOLOGISTS’ Union, Check List, 1886, 92.—Gapow, .in 
Brono’s Thier-Reich, Vog., ii, 1891, 205.—Bzpparp, Struct. and Classif. 
Birds, 1898, 356.—Suarre, Hand-list, i, 1899, xiv, 183.—Sa.vin and Gopman, 
Biol. Centr.-Am., Aves, iii, 1903, 397—Knowlron, Birds of the World, 
1909, 390. 
=Sternidae ReicHENOW, Vég. Zool. Gart., i, 1882, 27. 
Medium-sized to very small Lari with the bill nearly straight, 
relatively narrow (vertically), with terminal portion of culmen not 
strongly if at all decurved, its depth at gonydeal angle usually less 
(never more) than at middle of nostril, the exposed culmen at least 
one and one-fourth times (sometimes nearly three times) as long as 
tarsus; feet relatively small, the tarsus little if any more than one- 
ninth (usually less than one-tenth, sometimes only one-nineteenth) 
as long as wing; tail usually (often deeply, sometimes excessively) 
forked, rarely graduated; thigh-muscle formula with B (except in 
Gygis); expansor secundariorum muscle absent (except in Anous); 
pterylosis typically charadriine. 
The Sterniide are closely related to the Laride, but seem to be 
sufficiently distinct to merit family rank. Although single characters 
often occur in both groups, every species is, nevertheless, distinctly 
and unmistakably either a Tern or a Gull. 
The Sternide are as a rule birds of smaller size, lighter build, and 
more graceful form and actions than the Laride, and obtain their 
food in a different manner, pouncing suddenly on it from the air and 
striking it with their sharp bills. From this habit the vernacular 
name ‘‘Striker” is applied to them on the coast of Virginia and 
elsewhere. Their nidification is closely similar to that of the Laride. 
KEY TO THE GENERA OF STERNIDAE. 
a, Tarsus longer than first two phalanges of middle toe, more than one-fifteenth as 
long as wing, more than one-third (usually one-half or more) as long as exposed 
culmen, the latter more or less decurved terminally; webs’ between anterior 
toes not deeply incised; coloration not wholly white. 
b. Tail simply forked (more or less deeply), the lateral pair of rectrices longest or 
equal to the longest. } 
c. Frontal feathering advancing farthest anteriorly on sides of maxilla, where 
forming a distinct (though sometimes obtuse) angle immediately behind 
nostril. 
