forewing is irregularly speckled with dark reddish-brown and has three patches of 
the same color. The hindwing is bright orange. Full-grown larvae are yellowish or 
greenish yellow except for black heads and cervical shields, and are about 20 mm 
long. 
Winter is spent in the egg stage. Hatching begins in May, and larvae are present 
until September, depending on location. They live together in dense nests they 
construct by webbing twigs and leaves together (fig. 56). In heavily infested areas, 
these nests are often numerous. Some may be large enough to entirely enclose small 
trees. 
The uglynest caterpillar is usually of little or no economic importance because 
the trees attacked are usually of low value. However. the presence of its webs on 
roadside vegetation may be objectionable because of their unsightliness. Cutting 
and removing nests provides adequate control in most situations. 
The oak webworm, A. fervidanus (Clemens), occurs throughout the oak regions 
of the Northeastern and Lake States and in various parts of southern Canada. Its 
favored hosts appear to be scrub and bur oaks, but it also feeds on the seedlings and 
sprouts of several other oaks. The adult is brownish and has a wingspread of about 
21 mm. The forewing is yellowish brown with dark patches. The hindwing is 
uniformly smoky except for a light-colored fringe marked with a fine, basal line. 
Full-grown larvae are grayish green and about 20 mm long. Larvae live together in 
webs. some of which may be 8 cm wide and up to 0.5 m long (fig. 57). 
Occasionally, they are large enough to enclose all of the leaves at the top of a tree. 
Winter is spent in the egg stage. Larvae appear in midsummer, and pupation occurs 
within the nest. The species is of little economic importance. 
F-519520 
Figure 56.—Nest of the uglynest caterpillar, Archips 
cerasivoranus, on wild cherry. 
162 
