NATURAL SCIENCES OF PHILADELPHIA. 43 



in September (a few probably somewhat earlier), and is very com- 

 mon until December. A large number shot in the middle of Sep- 

 tember were in the same condition of plumage as T. regius was 

 at the same time. The species ma^^ be marked out among its allies 

 b}^ its size, its singularly trim shape, conspicuousl}^ black, long bill, 

 yellow-pointed, and a gQUQval whiteness ; the mantle being paler 

 than in any of the others. Specimens, even in the fall, frequently 

 show a rosy blush of the under plumage, much like that generally 

 supposed to characterize T. elegans of the California coast. 



The difference in "the pattern of the coloration of the primaries 

 of this bird, that was noted in my "Review" as separating the 

 species (or whatever it is to be considered) from the European T. 

 cantiacus, has not failed in a single instance that has come to my 

 knowledge. No reliance, however, can be placed upon the yellow 

 tip of the bill as a character ; this varies from nothing (in imma- 

 ture specimens) up to a third, or nearly, of the total length of the 

 bill, and no two specimens show exactly the same line of demar- 

 cation between the yellow and the black. Specimens, as usual 

 in this familj^, differ much in size, and particularly in the length 

 and stoutness of the bill. The feet are always black, as in T. 

 7'egius. 



Sterna Mrundo. 



Yery common, but onlj- during the migration. Arriving from 

 the south earl}^ in April, they all pass on during the following- 

 month. They are abundant again in September and October, 

 perhaps a little earlier and later, but I identified none except 

 during these months. In the spring they are scarcely to be told 

 with certainty, unless shot ; but in the fall they are conspicuous 

 by the fact that they retain the black pileum, at least as long as 

 they remain here. It has been stated, upon eminent authority, 

 that this species never loses the black on the head ; and, although 

 I do not confirm this from examination of specimens taken in 

 the depth of winter, my observations until the end of October 

 support it, and I do not remember to have seen in any museum 

 a Wilson's tern without the feature in question. Numbers shot 

 here in September had completed the winter plumage, and were 

 newl}- feathered, except on the crown, where the black looked worn 

 and faded, but was still unmixed with white, except a few specks 

 on the extreme front. I presume that the change on this part of 



1871.] 



