314. 
756 SYSTEMATIC SYNOPSIS. —LONGIPENNES — GAVIZ. 
Webs incised (Group STERNE), 
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: en peat crest. Feet black. 
Forking of tail variable. Oflarge size . . ss 6 « « « Lhalasseus 
Bill moderate, slender, usually bright colored, like ae feet. Nocrest. Tail long, deeply 
forked Size medinmiandsamall 5 oss co ee, ss em ws oy ee we a CER een 
Upper parts dusky. Cap like the back. 
Bill and feet black. A white frontalcrescent. . . . . . . . Haliplana 
Webs deeply incised (feet little more than semipalmate). Tail merely emarginate, hardly or not half 
as long as the wing. Under partsinsummer black .. . . . . Hydrochelidon 315 
Nostrils nearly median. No frontal antize, the feathers etonding ieee on Gulmen 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:.) 
Colormuliginousihiie Bictm ck eee Moved Sas cel.) eon eee eon me 
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 Subgenera and Species (adults). 
GCOLOCHELIDON. Bill very stout, almost gull-like, black. Tarsus much longer than toes, black. Tail 
lightly forked, contained about 23 times in wing. Size moderate. 
Head crested. Cap black. Pearly mantle extending overrumpandtail . . . - « » Qa@nglica 18z 
THALASSEUS. Bill long, large, tern-like, bright colored or with yellow tip. Feet piace 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 798 
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 794 
Tail forked. Primaries with white space on inner webs. Bill orange, pleadon ae 2.50, under 0.50 
deep at base, gonys about 1.50long. Wing12.50. . .- . - . « » elegams, Vises 
Tail deeply forked, with narrow outer feathers. Printed with Site space on inner webs. Bill 
slender, black, yellow-tipped. . . . » . cantiaca T96 
STERNA proper. Bill long, slender, acute. one toe ee ican. middle 8 an, ae 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 . . . . .trudeaui 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. Tarsus 0.900rmore. . . . . « forstert "(3 
Bill red, blackening at end; feet coral-red. Outer = of outer tail- feather gray or 
dark, inner white; under parts paler than upper. Tarsus about0.75. . hirundo 197 
Bill wholly red; feet vermilion ; outer tail-feather as in the last. Tarsus 0.65 or less. 
Under parts nearly like upper. . . Soe ee ee sy ee oe SROCOD Cn 
Bill black, or only red at base. Feet veaaiah wets ly we oe 6. 0s doug tee 
A white frontal crescent. 
Bill yellow, tipped with black. Feetyellow. . ......... + - antillarum 801 
Billvand. fect Diack |); /: co cen Sue Mone UOC NEMSIES citer us) cs swe 5, cele e r 
Mantle dusky. A white frontal crescent. Bill and feet black, (HALIPLANA.) p 
Mantle blackish-brown; capthesame. ....-.+.... +++ +... - . JSuliginosa 
Mantle sooty-gray; cap nee =: Se . . . anesthetica 805° 
Ops. Above analysis based on adult summer fides ate aot entirely availa for anne and winter ones, § 
in which the chars. of the cap, and colors of bill and feet, may be entirely different. These must be de- 9 
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termined by reference toythe detailed descriptions. 
