the head by a narrow white band, a reddish brown bcady with 
yellowish sides and two rows of white dots along the back, and it 
is about 20 to 22 mm. long (fig. 152). Pupae are pale green when 
just formed; later, they become dark reddish brown, and they 
are about 12 mm. long. This species was considered to be a racial 
form of the spruce budworm until it was described as a new 
species in 1958 (265). 
Jack pine budworm adults are present from early July to early 
August and lay their eggs in clusters of about 40 eggs each. 
Hatching occurs in about 10 days. A few days later, the young 
larvae, without feeding, spin hibernaculae under bark scales on 
the trunk or larger limbs, or between needles. Then they molt to 
the second instar, the stage in which they remain throughout the 
remainder of the summer, fall, and winter. In the spring, about 
the time the staminate flowers are shedding their pollen, they 
emerge and begin feeding on the pollen. Some usually remain in 
the flower clusters throughout the entire feeding period, but the 
majority migrate to new foliage on which they feed, once it is 
well developed. The needles are not consumed entirely, but are 
usually clipped off at the base and webbed together. Pupation 
occurs among the needles or between webbed shoots. 
The jack pine budworm usually does not cause heavy mortality 
of merchantable jack pine, but it may cause top killing and stag- 
headedness. During outbreaks, however, heavy losses in poles, 
saplings, and reproduction may result. In heavily infested stands, 
young understory red and white pines also are often severely 
F-506744 
f FIGURE 1538.—Pupae of the large 
. aspen tortrix, Choristoneura 
conflictana, in webbed leaves. 
F-501801 
FIGURE 152.—Larva of the jack 
pine budworm, Choristoneura 
pinus, feeding on needles of jack 
pine. 
