702 STERNA ANiESTHETA, BRIDLED TERN. 



black. Tli<> frontal -white lunula, is narrower than fiil'nihwsa, of about the same width 

 as in lunciUf, au<l, as in tliat species, extends some distance beliind the eye, which is not 

 the case \u fulif/hiosa. The black pilenni is, on the nape, sharply detined against ashy- 

 white, which, as it proceeds backward, gradually deepens int-o the cinereous-brown, 

 which is the prevailing color of the upper parts. The wings, and especially the prima- 

 ries, are darker than the rest of the upper parts, and have scarcelj^ a shade of cinereous ; 

 the tail, with jts coverts, however, is much lighter and more ashy, approaching the 

 nape in color. The primaries, as in luitata, have well-detined, pure white spaces run- 

 ning for a considerable distance from their bases along the inner web, while in 

 fnl'Kjinona the inner webs are simply grayish-brown, with no well-marked pictura. A 

 large part of the inner webs of the secondaries and tertials are also white. All the 

 under wing-coverts are pure white. The central tail feathers are, as already described, 

 brownish-ashy, concolor with their coverts. The lateral on'«s have much white toward 

 their bases, especially on the inner webs, and this increases on each feather .success- 

 ively to sn(;h an extent that the next to the outer one is wholly white except a small 

 space at its tip, while the outermost is entirely white. In ftdif/inosa only the outer- 

 most one is white. (Compare descriptions.) The shafts cf the primaries are brownish- 

 black above, white beneath ; of the rectriccs, dark along the cinereous, and white 

 along other portions of the feathers. Below the bird is entirely pure white. 



Dimevnions. — Length, 14 to 15 inches ; wing, from the carpus, 10. fit); tail, G to 7;* bill, 

 L4U to 1.(10 ; height at base, 0.35 to 0.40 ; width, slightly less ; tarsus, 0.85 : middle toe 

 the same, with the claw 1.20; outer toe and claw, 1.00; inner, 0.75. These measure- 

 ments, it will be seen, are intermediate between those of fuUfiinosa and liiiuda. 



Immature plumafie. — A specimen (No. 11394, Nicaragua, Oct., 1858, Dr. CahhveJl), 

 probably a bird of the tirst year, is slightly smaller, as would have been expected, but 

 m form is the same. The differences in the plumage are : The black of the pileum is 

 imperfect, largely mixed with white on the vertex, so that it fades insensibly into the 

 white of the lunula, which latter is thus obscured. The black frenum is corre pond- 

 iugly imperfect. The upper parts are ])aler and grayer, some of the leathers being 

 margined with whitish. The lateral rectrices are not wholly white. The under parts 

 are pure white, as before. This is probably not the youngest plumage (of which I 

 have yet to see specimens, that may perhaps be all dusky, white-spotted, like fidifi hi osa), 

 but rather represents a plumage that closely resembles, if it be not identical with, the 

 ordinary winter plumage of the adult. 



This bird scarcely requires comparison with fidiginosa. The light ashy-white nape ■ 

 and hind neck ; the black cap contrasting with the color of the back, besides being 

 separated by the whitish cervix ; the wings darker than the back ; the amount of white 

 on the tail ; the narrowness and length of the frontal lunule ; the differently-shaped 

 bill and the smaller size, at once distinguish it. The species in fact comes nearer houda, 

 Peale, a rather dark-colored species, in which the crown and back are also conspicu- 

 ously different from each other in color. S. linuda, however, is a smaller bird, with a 

 grayish-plumbeous mantle, more nearly as in ty])ical Stcriuv. It is well described and 

 ligured by Mr. Cassin in the Ornithology of the United States Exploring Expedition. 



Sipioiiymy. — In 1864 I reached, by some devious ])ath I do not now remember, the 

 conclusion that panaijvnsis, Gm. (or panaya, Lath.), were rather referable to fidUj'nwba 

 than to this species ; but upon reconsideration of the subject, I see that the less said on 

 this score the better. It was upon this erroneous consideration that I i)roposed the 

 term discolor, not that I desired to separate the American bird from that of other 

 regions. The names of Gmelin and Latham are current for the species, but they are 

 based upon Sonuerat (as above), and upon the same basis appears the name "(owsiha;- 

 <i(.s" (as given by Gray), which has priority. Sundevall, indeed, finds a still earlier de- 

 signation in vubdo-va, "Sparmni., Mus. Carls, t. 62." This I have not been able to look 

 np, but as there seems to be some uncertaintj' about it, it maj^ be best held in check. 

 Thus Gray, in the Hand-list, gives "nubdo.sa, Sparmm., M."C. t. 63," as a synonym of 

 No. 11082 {" infiiscata, Licht."); while in 1863, in his List of British Birds, he has a 

 "nehidosa, Sparmm., M. C. t. 63," under Sterna canfiaca, t Gm. Without th(s work before 

 me, I can only presume that Suudevall's quotation of "t. 62" is pi. 62, and that Gray's 

 '^ ncbulom" is a slip for nubdosa. 



In not adopting this name nubdosa for the present species, I .am influenced by the 

 following considerations : There appears to be another very closely-related species, or 

 rather variety, and it is uncertain to which one of the two nubdosa belongs. This 

 species is given by Gray, No. 11082, as ^'infuscata, Licht.," and put in a dittereut sub- 

 genus. There are in the Smithsonian two specimens which I take to be this species : 

 one. No. 57093, from the Schliitter collection, marked " Sterna fuscata, $, ad., Insel 

 Candia;" and another. No. 28475, marked "Bengal," but without further labeling. 



* But the length of the tail, as in all Terns, varies very greatly, according to the age 

 of the elongated lateral feathers. A discrepancy of several inches is by no means 

 unusual in this subgenus and in Sterna. 



t Latham quotes " nubdosa, M. C. t. 63, pullus," as a synonym of his S. boysU var. y. 



