35 
CANKERWORMS. 
(Figs. 26, 27, 28, and 29.) 
These slender, bare caterpillars appear on apple and other fruit 
trees in early spring and eat holes in the leaves. As they crawl they 
loop up the body, and are thus called "measuring worms" or "inch 
worms. " There are two species of the cankerworms, their habits, how- 
Fig. 26.— Alsophila pometaria: a, male; b, female. 
c, d, details. (Riley.) 
Fig. 27 .—Alsvpldla pometaria: a, b, 
f, larva; c, d, segments of same; 
(Riley.) 
e, eggs; 
g, pupa. 
ever, being similar. The eggs are laid in clusters on the tree in the fall 
and early winter, with the fall species {Alsophila pometaria Harr.); in 
March or April with the spring species (Paleacrita vernata Peck). 
The eggs of the former are flattened on top; those of the latter are 
rounded. The larvae hatch in early spring and at once feed on the 
Fig. 28.— Paleacrita vernata: a, male; b, female, 
c, d, e, details. (Riley.) 
Fig. 29. — Paleacrita vernata: a, cater- 
pillar; b, egg; c, d, segment of 
caterpillar. (Riley.) 
leaves. When full grown the} T descend to the ground and pupate 
therein, the moths issuing in late fall or very early spring. The 
females are wingless, and obliged to crawl up the tree to deposit eggs. 
The males have large, thin, gray wings. There is but one brood each 
year. 
THE PEACH-TREE BORER. 
(Sanninoidea exitiosa Say — fig. 30.) 
This destructive insect is readily discerned by the presence of a 
gummy exudation mixed, with f rass and excrement at or near the base 
of the tree. The parent moth lays the eggs singly (from May to July, 
according to latitude) on the bark of the tree, usually near the base. 
The young larva burrows into the bark and mines between it and the 
