756 SYSTEMATIC SYNOPSIS. —LONGIPENNES — GAVIZ. 
Webs incised (Group STERNEZ). 
Webs moderately incised. Tail well-formed, generally more than half as long as the wing. Under 
parts white or light. 
Upper parts pearl-gray. Cap in summer black, or a black bar through eye. 
Bill short and very stout, somewhat gull-like, black. Tarsi much longer than the toes, 
black. Tail lightly forked. Medium size . « Gelochelidon 
Bill long, large, bright colored, or with yellow tip. “an occipital crest. Feet black. 
Forking of tail variable. Of large size ‘ + » . Thalasseus 
Bill moderate, slender, usually bright colored, like the feet, No crest. Tail long, deeply 
forked. Size medium andsmall . .. Ce ete ee ae Sterna 314 
Opper parts dusky. Cap like the back. 
Bill and feet black. A white frontalcrescent . . . + . + « . Haliplana 
Webs deeply incised (feet little more than semipalmate). Tail siarely emarginate, hardly or not half 
as long as the wing. Under partsin summer black . . . . . . Hydrochelidon 315 
Nostrils nearly median. No frontal antiz, the feathers extending further on culmen than at the sides. 
Tail double-rounded. Tarsi very short. Toes lengthened, the lateral nearly as long as the middle, with 
full webs. (Group ANOEZ.) 
Color fuliginous. . bs nip) ay tae = Solaniaerese & oe ee we ew ww « Anoits 316 
314, STER/NA. (Latinized from English stern or tern.) TERNS. Form typical of the sub- 
family. Nostrils sub-basal. Frontal antize prominent. Tail more or less forked. Tarsus 
not shorter than middle toe without claw. Lateral toes much shorter than middle. Webs 
moderately incised. Under parts of adult white, or like back. (Characters of the subfamily, 
exclusive of Hydrochelidon and Anoiis.) 
Analysis of Subg ‘a and Species (adults), 
GELOCHELIDON. Bill very stout, almost gull-like, black. Tarsus much longer than toes, black. Tail 
lightly forked, contained about 24 times in wing. Size moderate. 
Head crested. Cap black. Pearly mantle extending over rumpand tail . . . - . anglica 792 
THALASSEUS. Bill long, large, tern-like, bright colored or with yellow tip. Feet black. Head crested. 
Size large to largest. 
Tail merely emarginate, contained nearly or about 3 times in wing. Primaries without white space 
on inner webs. Billred. Largest: wing about 16.00; tail 5.50; billnearly 3.00 . . . . . caspia 1793 
Tail forked. Primaries with white space on inner webs. Bill orange, stout, about 2.50, 0.50 or more 
deep at base; gonys about 1.00 long. Wing14.50. . . » maxima 194 
Tail forked. Primaries with white space on inner webs. Bill orange, slender, about 2. 50, under 0.50 
deep at base, gonys about 1.50long. Wing 12.50. . Si Diese . . . elegans 95 
Tail deeply forked, with narrow outer feathers. Primaries with white space on inner webs. Bill 
slender, black, yellow-tipped . - + . cantiaca 196 
STERNA proper. Bill long, slender, acute. Tarsus not longer than middle too and claw. Tail more or 
less forked, with acute or very narrow lateral feathers, one-half or more as long as wing. Head not 
decidedly crested. Size medium to smallest. 
Mantle pearly-blue. 
‘No black cap. 
Head whitish, with black bar through eye; under parts like the mantle - . + -érudeaui 802 
A black cap. 
No white frontal crescent; black cap reaching bill. 
Bill wholly or mostly red or reddish. 
Bill red, blackening at end; feet coral-red. Outer web of outer tail-feather white; 
: inner gray or dark. Tarsus0.900rmore. . . . Sorsteri 798 
Bill red, blackening at end; feet coral-red. Outer web of outer tail- “feather gray or 
dark, inner white; under parts paler than upper. Tarsus about0.75. . hirundo T9T 
Bill wholly red; feet vermilion; outer tail-feather as in the last. Tarsus 0.65 or less. 
Under parts nbarly like upper . c SO 6 s . . oe. « Macrura 799 
Bill black, or only red at base. Feet reddish . @ soe ee ee we ee « dougalli 800 
A white frontal crescent. 
Bill yellow, tipped with black. Feet yellow. ....... ss . antillarum 801 
Bill and feet black. r . ~ ee ws . Gleuticn 803 
Mantle dusky. A white frontal crescent Bil ane foot black. (HALIPLANA.) 
Mantle blackish-brown ; cap the same. . AS tins eae ita ses Ae ‘ Suliginosa 804 
Mantle sooty-gray; cap black a ‘. a . anasthetica 805 
Ogs. Above analysis based on adult summer birds, andl not, entirely available for young and winter ones, 
in which the chars. of the cap, and colors of bill and feet, may be entirely different. These must be de- 
termined by reference to the detailed descriptions. 
