A,B,D, F-531247 
C, courtesy Can. For. Serv., Can. Dep. Environ., 
Sault Ste. Marie, Ont. 
Figure 78.—Spring cankerworm, Paleacrita vernata: A, 
females and eggs; B, male; C, fully grown larva; D, 
pupae. 
12 mm long, and is marked with black spots on the sides and back. Male moths 
have fully developed wings with a wingspread of about 42 mm. The forewings are 
buff and marked with two transverse, wavy brown bands and a sprinkling of 
brownish dots. Full-grown larvae (fig. 79) may be bright yellow, with rusty-brown 
heads, and 10 dark wavy lines running down the dorsum, or they may be entirely 
light yellow. They are about 37 mm long. 
Winter is spent in the egg stage and hatching occurs in April or May. Larvae are 
present until July, then pupate in cells in the ground. Adults are present from 
October to December. The females crawl up the trunks of trees and deposit their 
eggs singly or in small groups in bark crevices. There is one generation per year. 
Several outbreaks have been recorded in the Northeastern States and Canada. At 
such times, male moths are attracted to street lights in nearby towns in considerable 
numbers. Two dipterous parasites, Pseudotachinomyia slossonae (Townsend) and 
Phryxe vulgaris Fallén, commonly attack the larvae. A virus epizootic occurred in 
an outbreak in Quebec in 1961. 
194 
