1002 SYSTEMATIC SYNOPSIS.— LONGIPENNES. 



One species, Nacnia inca, has a curious bundle of curly while plumes on each side of the head. 

 Another, Gygis Candida, is pure white all over ; Procelsterna einerea and P. ccerulea are mostly- 

 ashy; the Noddies (Anous and Micranous) are all fuliginous, with white or gray caps; the 

 upper parts of Haliplana are dark ; the species of Hydrochelidon are largely black. These are 

 the principal if not the only exceptions to the usual coloration just given. The sexes are dis- 

 tinguishable neitlier by size nor color; but nearly all the species, in the progress toward 

 maturity, undergo changes of plumage, like Gulls ; while seasonal differences are usually con- 

 siderable. As a rule, the black cap is imperfect in young and winter specimens, and the 

 former show gray or brown patching instead of the pure final color of the mantle. In all 

 those species in which the bill is red, orange, or yellow, it is more or less dusky in the young. 

 The changes are probably greatest in the Black Terns {Hydrochelidon). 



The general economy is much the same throughout the group. The eggs are laid in a 

 slight depression on the ground — generally the shingle of beaches — or in a tussock of grass in 

 a marsh, or in a rude nest of sticks in low thick bushes ; they are 1-3 in number, variegated in 

 color. Most species are maritime, and such is particularly the case with the Noddies ; but 

 nearly all are also found inland. They are noisy birds, of shrill, penetrating voice ; and nO' 

 less gregarious than Gulls, often assembling in multitudes to breed, and generally moving in 

 company. Species occur near water in almost every part of the world, and most of them are 

 widely distributed ; of those occurring in North America, the majority are found in correspond- 

 ing latitudes in the Old World. Some 70 species are currently reported ; the true number is 

 just about that of the Gulls (about 50). 



The generic and subgeneric groups of Sternince are rather better marked than those of 

 Larince. Phaethusa, Seena, Ncenia, and several genera near Anous {Procelsterna, Micranous, 

 and Gygis are extralimital. The North American forms may readily be distinguished by the 

 following analysis. 



Analysis of North American Genera. 



Nostrils sub-basal. Frontal antiae prominent, embracing base of culmen. Tail more or less forked. Tarsus not 

 shorter than middle toe without claw. Lateral toes much shorter than the middle. Webs incised. (Group 

 Sterne.«.) 

 Webs moderately incised. Under parts white or light. 



Bill short and stout, somewhat gull-like, black Gelochelidon 



Bill otherwise Sterna 



Webs deeply incised (feet little more than semipalmate). Under parts in summer black . . . Hydrochelidon 

 Nostrils nearly median. No frontal antiae, the feathers extending farther 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 

 Anoe«.) 

 Color fuliginous, with white or light cap . Anous- 



GELOCHELI'DON. (Gr. -yeXwy, gelos, laughter; xf^'^toj/, chelidon, a swallow.) GuLL- 

 BILLED Terns. Bill gull-like, rather shorter than head, robust, not very acute, compressed f 

 culmen nearly straight to beyond nostrils, then very declinato-convex to tip; g^inys about 

 straight ; rami slightly concave ; symphyseal eminence well marked ; tomia of lower mandible 

 inflected; commissure gently curved. Height of bill at base ^ of total length. Nasal groove 

 short and broad, not deep; nostrils short, widely oval, very near base of bill, just beyond the 

 feathers. Wings exceedingly long and acute, each primary surpassing the next by a full inch ; 

 secondaries short, soft, obliquely incurved at their extremities. Tail short, contained about 2J 

 times in wing ; deeply einarginate, but its lateral feathers not attenuated. Feet long and stout 

 for this subfamily ; tarsus shorter than bill, longer than middle toe and claw ; hind toe remark- 

 ably developed ; inner shorter than outer ; interdigital membranes well incised, especially the 

 inner. One wide-ranging species, of moderate size. (As subgenus of Sterna, in former edi- 

 tions of the Key.) 



G. nilo'tica. (Gr. NetXcar«of, Neilotikos, Lat. Niloticus, of the river Nile in Egypt.) Gull- 

 BiLLED Tern. Nilotic or Egyptian Tern. Anglican Tern. Marsh Tern. Nut- 



