BIRDS OF THE UNITED STATES. 
7 
upon the trunks of certain trees, and also upon fence-rails. In diameter, 
it measures three and a half inches; in height, one and a half inches. 
The width of the cavity is about two inches ; the depth in the centre, 
three-fourths of an inch. 
The most beautiful fabric, as well as the most compactly built, which 
we have seen, was obtained in the sj^ring of 1876, not far from Ger- 
mantown, Pa. It was placed uj)on a horizontal branch of an apple-tree, 
in close proximity to a farm-house. Externally, it is thickly covered with 
hluish-gray crustaceous lichens, which are held in place by a few cobwebs, 
and fragments of the silk of caterpillars. The base consists of dried stems 
of grasses, and on these is reared a neat and cosy superstructure composed 
of the inner fibres of the wild and cultivated sj^ecies of the vine, and a 
slight sprinkling of wool. These materials are variously interwoven, and 
arranged around the margin so as to form a cavity. The dimensions of 
this nest are as follows : External diameter, three and a half inches ; 
height, one and a half inches ; width of cavity, two inches ; depth in the 
centre, three-fourths of an inch. In the Plate it is represented the natu- 
ral size — built upon an oak branch. 
In the details of form and dimensions, this nest differs immateri- 
ally from specimens which we have met with and seen from other local- 
ities. But wherever obtained, they will always he found to bear a 
very close resemblance to one another, differing chiefly in the character 
of the articles which constitute the inner arrangement. We will merely 
mention one examjjle which was taken by Mr. Welch, in Lynn, Mass., 
and which will give our readers some faint conception of the extent 
to which variation is often carried. This structure was placed upon 
a dead limb of a forest-tree. Its walls were composed of small dry 
stems and vegetable down, finely interwoven, and covered on the outside 
with lichens which were cemented to it hy a viscid secretion that was 
ajijjarently suiijdied by the builders. The base was someAvhat flattened, 
much thinner than the walls, and comjDOsed of finer materials. The ex- 
ternal diameter was three inches, and the height one and a half inches ; 
