hickory. The adult is grayish with brown markings and has a 
Wwingspread of 37 mm. Full-grown larvae have pinkish bodies 
sparsely clothed with short, fine hairs and are about 37 mm. long. 
Adults appear in May and June and deposit their eggs on the 
bark of small twigs. Newly-hatched larvae bore into the twigs 
and tunnel in the pith. Later, they emerge and migrate to larger 
branches or the trunk where they enter and excavate tunnels 
several inches long. Frass is extruded through holes that are 
about 6 mm. in diameter in the trunk; it can usually be found in 
small heaps at the base of infested trees. Winter is spent in the 
larval stage, and pupation occurs in the tunnel in the spring. 
There appears to be one generation per year. 
Acossus centerensis (Lint.) and A. populi (Wlk.), the aspen 
carpenterworm, also occur in eastern United States. A. centerensis 
bores in poplars from New Jersey to Illinois. A. populi is found 
in poplars and cottonwoods from coast to coast. 
The carpenterworm, Prionoxystus robiniae (Peck.) (fig. 156), 
is widely distributed in the United States and southern Canada 
where it breeds in various hardwoods. In the Eastern and 
apt - Baer 
Pas" 
SS 
* “i es 
ete - AB. p ty? =. 
F-498365 
FIGURE 156.—Egegs, larva, pupal case, and adults 
of the carpenter-worm, Prionoxystus robiniae. 
388 
