THE CANKER-WORM. 
463 
females lay their eggs (Fig. 230, natural size and magnified) 
upon the branches of the trees, placing them 
on their ends, close together in rows, form¬ 
ing clusters of from sixty to one hundred 
eggs or more, which is the number usually 
laid by each female. The eggs are glued 
to each other, and to the bark, by a grayish varnish, which 
is impervious to* water; and the clusters are thus securely 
fastened in the forks of the small branches, or close to the 
young twigs and buds. Immediately after the insects have 
thus provided for a succession of their kind, they begin to 
languish, and soon die. The eggs are usually hatched be¬ 
tween the first and the middle of May, or about the time 
that the red currant is in blossom, and the young leaves 
of the apple-tree begin to start from the bud and grow. 
The little canker-worms, upon making their escape from 
the eggs, gather upon the tender leaves, and, on the occur¬ 
rence of cold and wet weather, creep for shelter into the 
bosom of the bud, or into the flowers, when the latter ap¬ 
pear. As this treatise may fall into the hands of persons 
who are not acquainted with the habits and devastations 
of our canker-worms, it should be stated that, where these 
insects prevail, they are most abundant on apple and elm 
trees; but that cherry, plum, and lime trees, and some 
other cultivated and native trees, as well as many shrubs, 
often suffer severely from their voracity. The leaves first 
attacked will be found pierced with small holes; these be¬ 
come larger and more irregular when the canker-worms 
increase in size; and, at last, the latter eat nearly all the 
pulpy parts of the leaves, leaving little more than the midrib 
and veins. 
A very great difference of color is observable among 
canker-worms of different ages, and even among those of 
the same age and size. It is possible that some of these 
variations may arise from a difference of species ; but it is 
also true that the same species varies much in color. When 
