THE LARGE HEATH 
83 
first week of July, when the butterfly is usually fully out and 
in fine condition. 
Hibernation. Hibernation is passed in the larval state ; 
towards the end of September it takes up its winter quarters, 
which are simply the bases of the grass stems upon which it 
rests, and apparently goes through complete hibernation, 
remaining torpid between five and six months. 
Egg and Egg Laying. The eggs are laid singly on the leaves 
and stems of the Beaked Rush (Rhynchospora alba), which 
is the natural food plant of the larva. The egg is large in 
proportion to the butterfly, is o*8o mm. high and an elliptic- 
spheroid in shape. About fifty irregular longitudinal keels 
run from the crown to the base, the spaces between are finely 
ribbed transversely. When first laid it is whitish-ochreous- 
green in colour, gradually turning to pale-straw-yellow, and 
pale-ochreous-brown spots 
appear under the shell ; 
these gradually become 
plainer and form an irregu¬ 
lar pattern of small blotches 
and a more or less broken 
band forming an irregular 
zone. The egg state lasts 
fifteen days. 
Larva. Upon hatching 
from the egg, the little larva 
eats away the shell in a line 
about two-thirds round just 
below the crown, and then 
forces itself out, the crown acting in exactly the same way 
as a lid. 
When fully grown after the fourth moult, it measures 
25*4 mm. It is rather slender and tapering at each end. 
The head is globular and granulated, and is covered with 
extremely minute hair-like points. The body is also granular 
and densely sprinkled all over with tiny whitish hairs. The 
ground colour is grass-green, longitudinally striped with a 
very dark velvety-green medio-dorsal line, palest at the ends ; 
this is bordered with a fine whitish line, and two lateral whitish 
stripes. The anal points are rose-pink and white. The head, 
Cremastral process of the pupa of the 
Large Heath (magnified). 
