6^JG SIERNA ALEUTICA, ALEUTIAN TERN. 



ground color varies from clear, pale greeuisb-wliite to pale dull drab or 

 olivaceous. The markings are numerous, and generally distributed, 

 tbougb they frequently tend to wreathe around the large end, especially 

 when they are of large size; they consist of small splashes, irregular 

 spots, and mere dots of clear brown of several shades, together with 

 numerous pale, ill-defined lilac or gray shell-markings. 



STERNA ALEUTICA, Bd. 

 Aleutian Tern. 



Sterna alevtica, Bd., Tr. Chic. Acad, i, 1869, 321, pi. 31, f. 1.— Dall & Bann., iMd. 307 



(Kodiak).— CouES, Key, 1872, 322. 

 Sterna " camtschatica, Pall.," Finsch, Abh. Nat. iii, 1872, 85 (Alaska). 



DiAG. S. rostro, pedihus, vcrtice, nucha, et fascia fraitsoculari, niyris ; lunula front alt, guld, 

 (jen'iH ctcaudd, alius ; corpore fjriseo-plumheo, suhtus dilutiore, niagis pei-laceo ; magnitudine 

 circiter S. macrurw. 



Hah. — Aleutian Islands. (Kodiak.) 



Adult— {'^o. .52517, Mns. Smiths. ; Kodiak, June 12, 1868. The type of the species.) 

 The bill has the usual shape, as in hirutido, macrura, &c. It is entirely black. The feet 

 are small, as in the species just named, but depart somewhat from the typical condi- 

 tion of this genus in having the Avebs more deeply incised. The emargiuation is not so 

 great, however, as in the genus Hydrochelidon. It is much as in Hnliplana. The tibite 

 are bare to the usual extent. The wings and tail are exactlj^ as in Sterna jirojier, the 

 latter, in its length and depth of fork, recalling macrura and forstcri. The crown and 

 nape are black ; there is a large white frontal crescent, the horns of which reach to the 

 posterior border of the eyes, ttie convexity of which extends into the nasal fossie, the 

 concavity of which is opposite the anterior border of the eyes. It is thus seen to be 

 broader than in most species similarly marked. The black vertex sends through the 

 eye a band that crosses the cheeks and reaches the bill just posterior to the point of 

 greatest extension of the feathers on the latter. The chin, auriculars, and other parts 

 of the head bordering this vitta below, are pure white, preseutly deepening insensibly 

 into the hue of the under parts. The tail is wholly pure white; no pearly wash on 

 either vane of any of the feathers. The upper parts at large are of a dark pearl-graj', 

 with a dull leaden line, difl'ereut from the clear pearly of macrura, &-c., yet not of the 

 smoky cast ot'2)ana)jcnsis, &c. ; it is a tint intermediate between these, that I tiud diffi- 

 cult to name satisfactorily. The whole under parts, from the white of the chiu, 

 just noticed, to the under tail-coverts, are of a paler and more decidedly pearly tint 

 of the same color, more nearly as in full-plumaged macrura, yet more grayish. Both 

 under and i;pper tail-coverts are, like the tail, white. The color of the back mounts 

 on the neck behind to the black of the nape without intervention of white. The under 

 wing-coverts and the edge of the wing are pure white ; so also are all the shafts of the 

 primaries. The primaries are blackish lead-color, with silvery hoariness, aud each with 

 a large white space on the inner web. This white space on the first primaiy occupies 

 at the base the whole width of the inner web, but grows narrower toward the tip of 

 the feather, ending about an inch from the tip, which is wholly blackish lead-color, 

 as just described, this color running down as a narrow margining of the inner vane for 

 two inches or more. On the other prin)aries successively this white space diminishes 

 in size, and is also less distinctly detined. The secondaries are colored much like the 

 back, but the greater part of the inner web of all is white, and there is a narrow 

 oblique touch of white on the outer web near its end, which forms a bar across the 

 wing when closed. 



Dimensions. — Bill along culmen, 1.40; along gape, 1.70; height at base, 0.30; length 

 of gonys, 0.80; wing, 9.75; tail, 6.50; depth of fork, about 2.40; tarsus, 0.60; middle 

 toe alone, 0.80 ; its claw, nearly 0.30. 



No special comparison with any other known species is required. 



This Tern, recently described (as above), is Lnteresting in several respects. It is 

 singular that so strongly mai'ked a species should have remained so long unnoticed, 

 but we iind no indication of it in the names or descriptions of previous writers. It 

 gives us a new style of coloration for North American species. At hrst sight it sug- 

 gests species of Ilaliplana, without, however, presenting anything like the special 

 coloration of the type of that subgenus, fuliginosa. It more nearly resembles the paler- 

 colored species of the genus, as panayensis for example ; and, again, comes nearer still 

 to certain southern forms of what are usually rated as Sterna projjcr ; for instance, S. 

 lunata, Peale. The black bill and feet, white frontal lunula, dullness of the upper 

 parts, &L(i., which suggest Halijjlana, are supplemented by an apx)roach to that genus 



