Allen on Nest and Eggs of the Cerulean Warbler. 25 
^ This appears to cover all cases, and, unless something different is 
shown, it seems to me to be fair to consider that, in regard to the 
spotting pigments, a single bird has but one color, which may be 
varied according to the way in which it is deposited on the shell, — 
either with respect to the thickness or position in depth from sur- 
face of the deposit, — and. even may itself vary temporarily among 
birds of the same species, owing to a temporary condition of the 
system. 
In regard to the ground-tint of the egg, which in many cases is 
colored, it can hardly be accounted for on the same principle. Of 
course those eggs which have a white or even a soiled ground-color 
offer no objection ; neither do those which have a colored ground 
but are unspotted, as we might justly say that the remarks in re- 
gard to there being but one coloring matter still apply. But there 
are certain eggs which are spotted on a colored ground, and which 
make it necessary to account for the ground-color in some different 
way, or else to widen the theory, and to allow these few cases to 
enter as exceptions. As to which of these two hypotheses is more 
apt to be the correct one, I am not as yet prepared to hazard an 
opinion, but am at present pursuing a course of chemical experi- 
ments by which I hope to settle the question. 
NEST AND EGGS OF THE CERULEAN WARBLER. 
BY J. A. ALLEN. 
The Museum of Comparative Zoology has recently received a 
nest and four eggs of the Cerulean Warbler ( Bendroeca ccerulea ), 
collected at East Penfield, Munroe County, N. Y., June 7, 1878, by 
Mr. P. S. Fuller. The female was shot as she left the eggs, which 
were nearly fresh. The nest was placed in the fork of a small ash- 
tree, about twenty-five feet from the ground. It is neatly and com- 
pactly built, consisting externally of fine dry grasses of an ashen 
tint, bound firmly together with spider’s silk, to which are affixed a 
few bits of whitish lichen ; it is lined wfith strips of bark and fine 
grasses, of a reddish-brown color. The nest is thus gray externally 
and brown within. It measures as follows : inside diameter, 2 
