stubs on the branch. They still retain their gregarious habit, 
however, and move in a group from branch to branch (fig. 178). 
For the most part, only the older foliage is eaten, but on shortleaf 
pine the terminal buds and tender bark on the new growth are 
also occasionally eaten (162). Full-grown larvae drop to the 
ground and spin mahogany-colored cocoons in the litter or top- 
soil. Pupation occurs in October or November and the adults 
appear immediately. Eggs are laid in slits cut into the needles, 
usually two to ten per needle. Each female lays from 90 to 120 
eggs, often all in the needles of one twig (742). 
This sawfly is found chiefly on medium-sized or large trees in 
forest stands. Several outbreaks have been recorded. One, which 
lasted from 1945 to 1948, spread over a gross area of about 3 
million acres in Arkansas before it subsided. Defoliation causes a 
reduction in growth, especially if the tree is defoliated during 
successive years, and tree mortality may occur (fig. 179). Impor- 
tant natural control factors are a polyhedrosis virus disease, cold, 
rainy weather in the spring, and two larval parasites, the dip- 
teron, Anthrax sinuosa (Wied.), and the hymenopteron, EH xente- 
rus canadensis Provancher. 
The Swaine jack-pine sawfly, Neodiprion swainet Middleton, one 
of the most important of the pine-infesting sawflies in eastern 
Canada, is known to have been present in the Lake States since 
the early fifties. It is now widely distributed in the Upper Penin- 
sula, Michigan, and in north-central Minnesota and Wisconsin. 
Jack pine is its favored host, but red, Scotch, and white pines 
growing in close proximity to heavily infested jack pines are also 
subject to defoliation by migrating larvae. Full-grown larvae 
differ in color in different portions of the infested region. Those 
found in the Lake States have bright orange heads and yellow 
bodies and there usually are two longitudinal pale stripes on each 
side. Bright yellow specimens without stripes are also occasionally 
found. 
In the Lake States, winter is spent as full grown larvae in 
cocoons in the litter or top soil, and pupation and adult emergence 
occurs in early to late spring. Eggs are laid in current year’s 
F-386627 
FIGURE 178.—Larvae of Neodiprion taedae linearis, the Arkansas pine sawfly. 
444 
