THE LARGE TORTOISESHELL 
157 
some other hibernating species, N. polychlorus frequently 
enters into hibernation shortly after emerging in July or early 
August ; and reappears towards the end of March or April. 
Egg Laying. Pairing takes place very shortly after hiberna¬ 
tion, and the eggs are usually deposited towards the end of 
April and early in May, when I have seen the females flying 
round the topmost branches of the 
tallest elms, selecting the slender 
terminal branches as sites for their 
eggs. Although the eggs are chiefly 
laid upon both the Common Elm 
and Wych Elm, they are also fre¬ 
quently deposited upon Sallow and 
Willow. The eggs are laid in a 
cluster, closely packed, with their 
sides glued together with a glutin¬ 
ous substance, which also attaches 
them to the branch. If a . thin 
twig is the site, the eggs encircle it 
in a band, but if a branch about 
5 mm. in diameter is chosen, the 
eggs then only partly surround it. 
During the process of depositing, 
the female remains clinging to the 
branch with closed wings until the 
whole batch is laid. The time 
occupied in depositing a large batch 
of 212 eggs is one and a half hours. 
Egg. The egg is o‘8o mm. high 
and is dome shaped. There are from Seventh segment of the 
seven to nine longitudinal keels shell on emergence from the 
which rise on the crown, where they egg. (Highly magnified), 
are much elevated, but they de¬ 
crease rapidly down the side and form only slight ridges 
over the basal half. The usual number is eight, occasionally 
only seven, and sometimes nine. The spaces between the 
keels are delicately ribbed transversely. 
When the egg is first laid, the colour is a pure yellow-ochre, 
which changes to apricot-yellow when a day old ; it gradually 
deepens in colour, assuming an amber-brown when a week 
