LARIDJ: — THE GULLS AND TERXS — UYDROGHELIDON. 



319 



uniform plumbeous, tliu bonier of the wing, from the shoulders to the ciirpo-mctuciirpal joint, white. 

 Lining of the wiug light iihiinbeouB-gray. Bill deep black, the rictus liike-rud, tlie interior of the 

 iiiDUtli pinkish ; iris dark brown ; lej^s and feet purplish dusxy. Adult, iti iclnkr : Head, neck, 

 and lower parts pure white ; orbital and auricular regions dusky ; crown and occiput dark giayish, 

 tlie feathers boitlered witli paler. Upi)er parts as in the summer plumage, l)Ut rather paler i)lum- 

 bcous. Youmj, Jirgt jjlumayc : Very similai' to the winter plumage, but scapulars, interscapulai-s. 



-«£^'';^J^^^ 



//. Ilium, (id'dl in miminii: 



and tertials tipped with raw-umber brown, the anterior lesser wing-coverts dusky, the crown, occi- 

 pnl, ami upper part of the nape dusky, antl the entire sides washed with pluml)eous. Downy young: 

 Aliiive, deep, soft umber-brown, witli a few coarse, irregular marblings of black ; forehead, crown, 

 throat, and jugulum more sooty brown, without markings ; side of the head (including lores) dull 

 wliitish ; abdomen white centrally, ]iale sooty grayish exteriorly. * 



Total length, about !).-25 inches ; extent, 24.()()-25.0() ; wing, 8.25 ; tail, 3.70, its fork, .90 ; cul- 

 nii'ii, 1.10 ; depth of bill at base, .25; tarsus, .08 ; middle toe (with claw), .90. 



Summer plunu(ne. 



With a series l)efore us of five adult specimens of the European bird in summer plumage, we 

 aiv much surpriswl that authors maintain the alisolute identity of the American Black Tern with 

 till' true //. niijra. Not one of these five sjR'cimens can be matched among a series of over fifty 

 examples of the American binl in corresponding dress, while three of tiiem are in a plumage never 

 ainnoached by the Anieriaui form. These three examples are bluish jilumbeous beneath, the shade 

 tiling exactly that of the upjuir parts, which are very decidedly lighter than in any American exam- 

 plivf. All of these three speiimens have the feathers of tiie throat white beneath the surface, while 

 une of them (No. 57088,9) has the chin and ui)i)er part of tiie throat uniform grayish white, in 



» From No. 77564, Cold Springs, fal., .luly 27, 1877 ; H. W. Uknsiiaw, oollpetor. 



