498 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
is widely distributed, being recorded from eastern Canada and the 
Atlantic States south to Texas and west to Minnesota. The larva is 
a borer in oaks, and its habits are similar to those of P. robiniae. Ac- 
cording to Hutchings (250), in Canada the larva spends the first sea- 
son in the outer layers of bark, the second year in the sapwood, and 
the third summer it continues boring into the woody part of the tree 
until September. It usually passes. the third winter asa pupa in the 
tunnel, although occasionally pupation is delayed until spring. Some 
trees are “brood trees,’ being continuously infested and becoming 
badly honeycombed. AI] parts of the tree over 1 inch in diameter 
may be attacked. For control, tree sanitation should be practiced. 
Infested branches may be cut off during the winter and burned. All 
wounds should be painted. In valuable trees, some of the caterpillars 
may be killed by inserting a pointed barbed wire into the burrow 
wherever sawdust 1s noticed, or carbon disulfide may be injected into 
the burrows which should then be stopped up with putty, grafting 
igure 121.—Larvae and work of the carpenter worm (Prionorystus robiniae). 
