LARID^ — THE GULLS AND TERNS — HYDROCHELIDON. 



319 



uniform plumbeous, the border of the wing, from the shoulders to the carpo-metacarpal joint, white. 

 Lining of the wing light plumbeous-gray. Bill deep black, the rictus lake-red, the interior of the 

 mouth pinkish ; iris dark brown ; legs and feet purplish dus^y. Adult, in winter : Head, neck, 

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

 the feathers bordered with paler. Upper parts as in the summer plumage, but rather paler plum- 

 beous. Youncj, first plu]iia<je : Very similar to the winter plumage, but scapulars, interscapulars, 



JI. nigra, udidt in summer. 



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

 put, and upper part of the nape dusky, and the entire sides washed witli plumbeous. Downy young: 

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

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

 whitish ; abdomen white centrally, pale sooty grayish, exteriorly.^ 



Total length, about 9.25 inches ; extent, 24.00-25.00 ; wing, 8.25 ; tail, 3.75, its fork, .90 ; cul- 

 men, LIO ; depth of bill at base, .25 ; tarsus, .68 ; middle toe (with claw), .90. 



«:^!^- 





Summer plumage. 



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

 are much surprised that authors maintain the absolute identity of the American Black Tern with 

 the true H. nicjra. Not one of these five specimens can be matched among a series of over fifty 

 examples of the American bird in corresponding dress, while three of them are in a plumage never 

 approached by the American form. These three examples are bluish plumbeous beneath, the shade 

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

 ples. All of these three specimens have the feathers of the throat white beneath the surface, while 

 one of them (No. 57088, 9 ) has the chin and upper part of the throat uniform grayish white, in 



1 From No. 77564, Cold Springs, Cab, July 27, 1877 ; H. W. Henshaw, collpctor. 



