prolegs near the center of the body, has given rise to a number of common names 
for the group such as geometers, measuring worms, inch worms, loopers, canker- 
worms, and spanworms. The larvae of many species have the interesting habit of 
standing nearly erect on the posterior prolegs when disturbed. Motionless in this 
position, they are almost indistinguishable from small twigs or spurs. With the 
exception of several Hawaiian species, which are predators of fruit flies, all 
members of the family are foliage feeders. 
Archiearis infans (Moschler) occurs from coast to coast in southern Canada and 
in the Northern States south to Pennsylvania. Its hosts are paper and gray birches. 
The adult has cryptic forewings and orange and black hindwings, and has a 
wingspread of about 25 mm. Mature larvae are green to reddish brown and about 25 
mm long. Two fine yellowish lines run the length of the dorsum, and there are two 
similar lines plus a broad subspiracular stripe on each side. Larvae are present from 
May to July, and winter is spent in the pupal stage. 
The fall cankerworm, Alsophila pometaria (Harris) (fig. 75), occurs from the 
Maritime Provinces to Alberta in southern Canada, and throughout the Eastern 
States south to Georgia and west to Missouri and Montana (397). Its hosts are elm, 
apple, hickory, maple, ash, beech, boxelder, basswood, cherry, and the oaks (399). 
The male moth is brownish gray and has a wingspread of 25 to 35 mm. The 
forewings are rather glossy with purplish reflections and are crossed by two faint, 
jagged, whitish bands. The hindwings are grayish brown, and each has a faint 
discal dot. Female adults are wingless and about 12 mm long. Full-grown larvae 
vary from very light green to very dark brownish green and are about 25 mm long. 
The head and anal segment vary from pale green to almost black, and are some- 
times mottled. A median, longitudinal, black stripe extends down the back of the 
darker larvae. Light-green larvae have longitudinal white lines. These color forms 
are associated with population density, with the darker larvae occurring in denser 
populations (334). There are three pairs of prolegs—a very small pair on the fifth 
abdominal segment and larger pairs on the sixth and anal segments. 
The fall cankerworm spends the winter in the egg stage, and hatching occurs 
from mid-April to early May. Young larvae skeletonize the young leaves at the tips 
Figure 75.—The fall cankerworm, Alsophila pometaria: 
A, adult female ovipositing; B, egg mass. 
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