NATURAL SCIENCES OF PHILADELPHIA. 
543 
It is bright, yellow at the tip for exactly the same distance as is the bill of 
“ Havdli but the base, for nearly a third of the length of the bill, appears to 
have been in life bright orange yellow, so that only the middle of the bill is 
left black ; whereas, in “ Havelli ” the bill is black from its yellow tip quite to 
the base of the upper mandible, and only a small space on the under mandible 
is left yellow. The front and crown are white, passing into light pearl blue on 
the nape, exactly as in “ Havelli the circumocular fascia also exists, but it 
is somewhat narrower than in that species. The other upper parts are of 
exactly the shade of Forsteri or “ Havelli but this color extends around the 
sides of the neck quite to the throat, and occupies the whole under parts of 
the bird, not even excepting the under tail-coverts, whereas in “ Havelli ” and 
Forsteri , the color of the same parts is nearly or quite pure white. The rump 
is white, as in both those species. The tail is elongated exactly intermedi- 
ate between a full plumaged summer Forsteri and “ Havelli;” it has precisely 
the color of the latter, the inner web of the lateral feather being somewhat 
lighter than in the former. The wings, in their markings and length, are iden- 
tical with those of either Forsteri or “ Havelli the tarsi and toes are fraction- 
ally of the same length, and appear of about the same color in the dried skin. 
The differences therefore between “ Havelli ” and “ Trudeaui” lie entirely in 
the following features : 1st. The bases of both mandibles are orange yellow for 
nearly half their length in “ Trudeaui ” while in “ Havelli ” a very small portion of 
the under mandible only is light colored. 2d. The color of the back extends 
undiluted over the whole under parts of “ Trudeaui,” while the same parts in 
“ Havelli ” are white. 
The greater slenderness of the bill, and the shorter tarsi, given by Audubon 
as characteristic of “ Trudeaui ” in comparison with “ Havelli ,” do not exist, 
provided the specimens before me exhibit the characters of the latter. Indeed, 
a comparison of fourteen specimens of Forsteri , three of “ Havelli” and the 
single “ Trudeaui ,” shows the three to be surprisingly similar in every detail 
of size and proportions ; the bills and tarsi particularly, hardly differing as 
much in length as do these parts in different individuals of hirundo or macroura . 
Should the color of the bill and of the under parts of “ Trudeaui ,” — more par- 
ticularly the latter — prove constant, they would be abundantly sufficient to 
separate it from any other species. The only question is, whether the speci- 
men under consideration is not in an entirely accidental and abnormal state of 
plumage, to be placed in the same category with albinism, melanism, &c. 
Although Audubon states that he saw other individuals like the present speci- 
men, it appears to be the only one ever actually examined. The question is 
one of great interest, but one of which, unfortunately, we are no nearer the 
positive solution than we were twenty years ago ; and I am therefore obliged 
rem in medio relinquere. 
“Sterna Havelli Aud.” 
Sterna Havelli , Audubon, Orn. Biog. v. 1839, 122. Lawrence, Gen. Rep. Birds. 
1858,861. 
So accurate a description of the winter plumage — the only one known — of 
this supposed species has been given by its discoverer, that it is unnecessary 
here to repeat it. A discussion of the essential characters assigned to it, to dis- 
cover exactly what are its claims to specific distinction, may be given. 
It is not a little singular that, of a species recognized for more than twenty 
years, the nuptial plumage should be still quite unknown. I am not aware 
that a specimen which could be referred to this species has ever been taken in 
spring or summer. There can be no doubt, however, that at that season it 
obtains the black pileum common to all the species of the genus, — with, proba- 
bly, not even the exception of “ Trudeaui .” A specimen before me, which agrees 
more closely than any other with Audubon’s plate and description, has the 
ciown and occiput very noticeably variegated with black; this color, indeed.. 
1862.] 
