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— from the tip to the nostril one inch and an eighth ; lower mandi- 

 ble one-eighth of an inch shorter than the upper ; tarsi clev- 

 en sixteenths ; wings about the same length as the tail ; lateral 

 tail feathers about one inch and a quarter longer than the next 

 longest, its outer web dusky. Adult witb tiie upper part of the 

 head and hind neck black ; sides of the head, fore, neck, and tlie 

 lower parts wiiite ; the breast slightly tinged with grayish-blue ; 

 rump and upper tail coverts white; tail feathers with the inner 

 webs white, the outer webs pale bluisii-gray ; the outer webs of 

 the lateral tail feathers dusky gray ; on the inner webs of the pri- 

 maries, along the shafts, a giayish-black band, whicli color widens 

 toward the end, where they are hoary, and shaded with dusky ; 

 outer web of the first primary black ; feet bright red. Length six- 

 teen inches, wing ten and a half. In winter, the upper part of the 

 head is dark brown ; the bill at the base pale orange — toward the 

 end black, the tips yellow; feet yellowish. Young, in summer, 

 with the bill greenish-yellow ; fore part of the head light brown; 

 hind head, and a spot before the eye, blackish-brown ; upper parts 

 grayish-blue, mottled with brown and dusky. 



Tills abundant species arrives among us in the latter part of 

 April ; commences laying in the month of May, and depositcs thrdc 

 eggs. It is occasionally seen on the interior streams and lakes. — 

 In its migratory course, visits the higlier latitudes, and returns 

 soulli in autumn. 



Tiie specific characters of no department of our Ornithology arc 

 more difficult to determine, with specimens not in full and mature 

 plumage, than arc the species comprised in the present and suc- 

 ceeding Genus. Tiie marked difference in plumage, and oilier 

 characters which individuals of ilie same species present during ihe 

 various changes occurring from the period at which they are first 

 fledged until arriving at maturity, as well as the winter dress of 

 the adult being so very different from that of the spring, a careful 

 examination of each species in all its varieties of plumage, and 

 frequent comparisons, are requisite in order to identify 

 them. Twelve species of the Genus Sterna inhabit North Ameri- 

 ca, all ol which, it is said, have been found within the limits of the 



