762 SYSTEMA TIG SYNOPSIS. — LONGIPENNES— GA VI^. 



tip of bill less in extent and intensity of color ; front white, either pure or speckled with hlacli; ; 

 crown variegated with black and white, the former color consisting of small, naixow, distinct 

 streaks along tlie shaft of each feather ; but the long occipital crest, which does not entirely 

 disappear at this season, usually remains of an unmixed brownish-black. Lateral tail-feathers 

 shorter than in summer. Youug-of-the-year : Considerably smaller than the adult, as is usual 

 in this subfamily, tlie wing being a full half-inch shorter. BUI shorter and weaker, and 

 without sharply-defined angles and ridges, brownish-black, the extreme point only yellow- 

 isli. CroM'u, front, and occiput brownish-black, variegated with white ; white touches very 

 small on the forehead. Upper parts as in adult, but everywhere marked with irregularly- 

 shaped but well-defined spots and transverse bars of brownish-black. No well-formed occipital 

 crest until after the first moult. Primaries like those of adult. The tail, however, is very different. 

 Tlie feathers for tliree-fourths their length are of the color of the back ; this color gradually 

 deepens, until toward the tips it becomes bronmish-black, each feather having a terminal irreg- 

 ular edge left whitish. Tail simply deeply emarginate, the outer feathers being but slightly 

 longer than the second. A fine species, alone among the large terns, with its black yellow- 

 tipped bill, of •svide distributioii in both Hemispheres ; in N. Am. observed along Atlantic 

 coast, New England to Texas; both coasts of C. Am. ; S. Am. Eggs 2-3, droiiped on the dry 

 sand ; 3.10 X lAO ; rather pointed, yellowish-drab, most irregularly spotted with dark brown 

 and reddish-brown, with lilac shell-spots. Breeds in largo colonies, like most terns. 

 797. S. hiruu'do. (Lat. hirimdo, a swallow.) COMMON Tekn. Wilson's Teen. Sea 

 Swallow. Adult, summer plumage : Bill as long as head, about ei|ualling tarsus and middle 

 toe without claw, of moderate robustness ; height at base contained a little more than five 

 times in length of culnien; gonys as long as rami, measured from feathers on side of mandible 

 to eminentia symphysis, which latter is Init slightly marked ; bright ccu'al, or light vermilion, 

 on Ijasal half or rather more, the remainder black, except the extreme tips, which are yellow- 

 ish. Pilcum lustrous velvety-black, with tinge of glossy-green ; it extends to lower level of 

 eyes, but leaves the lower lids white, and it is so broad on the lores that the white line of 

 feathers ahmg side of mandible hardly reaches to their extremity. Whole upper parts pearl- 

 blue, this C(dor commencing insensibly on back of neck, deepening on dorsum, and extending 

 quite undiluted almost to the extreme apices of the tertials; ending abruptly and distinctly 

 on rump, the upper tail-coverts being pure white. Under parts of a considerably lighter 

 sliade of the color of the back. On the throat, toward the chin and along the borders of the 

 black pileum, it fades into nearly or quite pure white, as it does also on the lower tail-coverts 

 and the circumanal region ; inferior surfaces of vrings and axillary feathers pure white. 

 Shafts of all the primaries white, deepening into blackish toward their apii'es. Outer web of 

 first primary black, with scarcely any hoariness. The first four or five primaries are grayish- 

 black, with a very strong silvery hoariness ; their inner webs with a space of white along their 

 inner margins. This space on the first primary at the base occupies the wlnde web, becomes 

 naiTower as it ascends, and ends, or becomes a mere line, about an inch from the apex of the 

 quill. On the other primaries it is of less extent, and runs up along the centre of the shaft a 

 little further than on the edge. On the innermost primaries, again, it is very narrow, but 

 forms an entire margin to the inner webs, running quite to thcii' tips. The inner primaries 

 have scarcely any grayish-black, but are rather of the etdor of the mantle. Secondaries mostly 

 pure white, but toward their ends have a space grayish-blue of about equal extent on both 

 webs. Tail moderately elongated and forked, contained about If times in the ■n'ing ; the 

 folded wings reach one to two inches beyond it; central feathers broad to their evenly rounded 

 tips ; the lateral ones successively narrower, more tapering and acute ; their outer webs light 

 pearl-gray (very like the back), their inner webs nearly pure white. The external pair, how- 

 ever, are on most of their inner webs, especially terminally, grayish-blue, while their outer 

 webs are dark grayish-black. Legs and feet light ooral-red. Dimensions : length (average) 



