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 gi-ound 

 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 gTound-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 {Deiidrceca cceridea), 

 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 with 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 



