50 mm. Full-grown larvae are yellowish to dark brown with five pale, yellowish 
longitudinal lines and are about 30 mm long. Larvae are present during June and 
July, and they feed at night. There is one, and possibly a second, generation per 
year. 
Phigalia titea (Cramer) occurs in southern Canada westward to Saskatchewan 
and the Eastern States. Its hosts include various hardwoods, especially northern red 
oak, red and sugar maples, basswood, hickory, and elm. Numerous outbreaks have 
been recorded in mixed oak and maple stands in the Northeastern States and 
Virginia. The male moth has a wingspread of 37 mm. The thorax is whitish, and the 
abdomen is marked with two rows of black dots on the dorsum. The forewings are 
dotted with dark-brown specks and are marked with three blackish lines and a row 
of black spots along the outer margin. The wings of the female are vestigial and 
functionless. Full-grown larvae are pinkish with many blackish longitudinal lines 
and are about 37 mm long. The thoracic segments are thick, and there are hairy 
tubercles on all body segments. Pinkish-red eggs are laid in crevices in the bark of 
dead branches. Larvae are present from May to July, and winter is spent in the 
pupal stage beneath litter (//87). 
The spring cankerworm, Paleacrita vernata (Peck) (fig. 78), occurs throughout 
the same general range as the fall cankerworm, also farther southwest and west to 
Texas, Colorado, and California. Its hosts are about the same as those of the fall 
cankerworm. Apple and elm are especially favored. Male moths have a wingspread 
of about 21 to 30 mm. The forewings are silky with loosely attached, brownish 
scales, and are crossed by three jagged, dark lines. The hindwings are pale, ashy 
gray, and each bears a dusky discal spot. Each of the first seven joints of the 
abdomen bears two transverse dorsal rows of stiff, reddish spines, pointed posteri- 
orly. Female moths are wingless and generally whitish or brown or black. There is a 
darker stripe down the back and two transverse rows of reddish spines on each of the 
first seven joints of the abdomen. These spines are often so prominent as to give the 
dorsum a reddish aspect. 
Full-grown larvae are reddish to yellowish brown, yellowish green, or blackish 
and are about 18 to 30 mm long. The head is light and mottled with brown. The 
body is usually marked with a yellow stripe just below the spiracles, and a broad 
greenish-yellow stripe down the middle of the venter. There are two pairs of 
prolegs, one on each of the eighth and anal segments. 
Spring cankerworms do not spin cocoons, but spend most of the winter as larvae 
in earthen cells. Pupation occurs in late winter, and the adults appear in early spring 
about the time frost leaves the ground. Female moths crawl up the trunks of trees, 
mate, and deposit loose clusters of 100 or more eggs in bark crevices or under bark 
scales on the trunk or branches. Hatching occurs by early May and the larvae 
become full grown by early June, at which time they drop and enter the soil. Like 
the fall cankerworm, this species may be an important pest of shade trees and 
forested areas. _ 
Fall and spring cankerworm populations are normally kept under control by 
natural control factors. Outbreaks often occur, however, over large areas. Isolated 
trees can be protected by placing sticky bands around the trunks to prevent female 
moths from climbing to lay their eggs (/224). 
The linden looper, Erannis tiliaria (Harris), occurs from Nova Scotia to central 
Alberta and south to Missouri, Kansas, and Utah (753). The larvae feed on the 
foliage of a wide variety of hardwoods, especially basswood, elm, hickory, maple, 
oak, birch, and apple. The female adult is light gray to brownish, wingless, about 
193 
