THE CANKER-WORM. 
465 
hours afterwards, they are changed to chrysalids (Fig. 233) 
in their cells. 
The chrysalis is of a light-brown color, and 
varies in size according to the sex of the insect 
contained in it; that of the female being the lar¬ 
gest, and being destitute of a covering for wings, which is 
found in the chrysalis of the males. The occurrence of 
mild weather after a severe frost stimulates some of these 
insects to burst their chrysalis skins and come forth in 
the perfected state; and this last transformation, as before 
stated, may take place in the autumn, or in the course of 
the winter, as well as in the spring; it is also retarded, in 
some individuals, for a year or more beyond the usual time. 
They come out of the ground mostly in the night, when 
they may be seen struggling through the grass as far as 
the limbs extend from the body of the trees under which 
they had been buried. As the females are destitute of 
wings, they are not able to wander far from the trees upon 
which they have lived in the caterpillar state.. Canker- 
worms are therefore naturally confined to a very limited 
space, from which they spread year after year. Accident, 
however, will often carry them far from their native haunts, 
and in this way, probably, they have extended to places 
remote from each other. Where they have become estab¬ 
lished, and have been neglected, their ravages are often 
very great. . In the early part of the season, the canker- 
worms do not attract much attention; but it is in June, 
when they become extremely voracious, that the mischief 
they have done is rendered apparent, when we have before 
us the melancholy sight of the foliage of our fruit-trees and 
of our noble elms^^ reduced to withered and lifeless shreds, 
and whole orchards looking as if they had been suddenly 
scorched with fire. 
[ 26 The insect which ravages the foliage of our “ noble elm ” in the South is the 
larva of a beetle, Gahruca calmariensis^ and hence the precautions here recom¬ 
mended are inapplicable. The female flies upon the leaves to deposit her eggs, 
59 
