1008 



S YS TEMA TIC S FN OP SIS. — L ONGIPENNES. 



Fig. 693.) Sandwich Tern. Kentish Tern. Boys' Tern. Cabot's Tern. Ducal 

 Tern. Bill slender, much longer than head, exceeding tarsus, middle toe, and claw together ; 

 tip very acute ; convexity of culrnen regular from tip to base, but slight ; commissure a little 

 curved throughout; outline of mandibular rami concave; that of gonys about straight; 

 eminentia symphysis hardly appreciable. Hind toe very small. Adult ^ 9 , breeding plu- 

 mage : Bill black, the tip for | to | of an inch bright yellow, sharply defined; "inside of 

 mouth deep blue." Feet dull black. Pileum and occipital crest glossy black, with a tinge of 

 green extending just below eyes, but leaving a space along side of upper mandible white to the 

 end of the feathers ; this black cap worn but a short time, in late spring and early summer. 

 Mantle light pearl-blue, fading on rump and upper tail-coverts into pure white ; but the rec- 



trices have a slight pearly 

 tinge. Primaries colored as 

 in S. maxima, heavily sil- 

 vered or frosted when new. 

 On the inner web of the first 

 the black space is broad, 

 and deep in color ; about 

 1^ inches from the tip it ab- 

 ruptly widens, so as to ex- 

 clude the white portion from 

 - Sandwich Tern, nat. size. (Ad. nat. del. E. C.) ->^^ the tip altogether. The 2d- 



4th primaries have the same pattern, but the white runs up farther on the central portion than 

 on the edge of the web, so that toward its end it receives a narrow edging of blackish.* The 

 other primaries have no blackish, being pearl-blue, with broad white margins along the whole 

 length of their inner webs. Length 15.00-16.00; extent 34.00; wing 12.50; tail 6.00, f(jrked 

 2.50; bill along culmen 2.25; along gape 3.00; height at base 0.48; width there 0.37; 

 length of rami from feathers on side of lower mandible 1.00; gonys 1.20; tarsus 1.00; mid- 

 dle toe and claw slightly longer. Adult, winter plumage : Yellow tip of bill less in extent 

 and intftsity of color; front white, either pure or speckled with black; crown white, vari- 

 egated with distinct black sh aft- streak s ; but the long occipital crest, which does not entirely 

 disappear at this season, is usually unmixed brownish-black. Lateral tail-feathers shorter 

 than in summer. Young-of-the-year : Smaller than i[ie adult, as usual in this subfamily ; 

 wing 0.50 shorter. Bill shorter and weaker, brownish-black, the extreme point only yellow- 

 ish. Crown, front, and occiput brownish-black, variegated with white; white touches very 

 small on forehead. Upper parts everywhere marked with irregular but w'ell-defined spots 

 and transverse bars of brownish-black. No well-formed occipital crest until after the first 

 moult. Primaries like those of adult. Tail-feathers for f their length of the color of the back, 

 but toward the tips brownish-black, each having a whitish terminal edge. Tail simply deeply 

 emarginate, the outer feathers being but slightly longer than the second. A fine large species, 

 easily known by its black yellow-tipped bill. The greater width of the black area on the outer 

 primaries is the chief if not the only distinction of ucuflavida from sandvicensis, as I pointed 

 out in Proc Phila. Acad. 1862, p. 541 ; it is not very well marked, but may be allowed sub- 

 specific validity. The typical form inhabits much of Europe, Asia, and Africa; the North. 

 American is observed chiefly along the S. Atlantic and Gulf coasts, casually N- to New Eng- 

 land in summer, regularly S. in winter to the West Indies and both coasts of Central America ; 

 not known inland. Breeds in colonies, like most Terns, laying on the dry sand of the shore. 

 Eggs 2-3, 2.10 X 1.40, rather pointed, yellowish -drab or creamy, irregularly spotted and 

 scrawled with dark brown, reddish-brown, and blackish, with lilac shell-spots. Nestlings 

 mottled gray above, white below. (Sterna (Thalasseus) cantiaca of former editions of the 

 Key. The species is type of the genus Actochelidon Kaitp, 1829, and stands somewhat alone, 



