Attacks the same trees under the same conditions as the flat-headed
borer. The adult, fig. 12, is about five-eighths of an inch long, brown
above, with two white stripes the whole length of the back. Head and
under surface grayish. It is a night flyer. The female appears about
June 1, and stays until September. She deposits her eggs at night, in
small incisions made angling into the bark, generally near the ground.
In about two weeks they hatch, and the little borers, _a_, fig. 13,
begin to bore their way into the inner bark and sap-wood, leaving the
bore filled with "castings," fig. 14. For two summers they stay in the
sap-wood and do great damage, often girdling young trees. After the
second winter they cut channels up into the hard wood; attaining their
growth by fall, they burrow outward to the under side of the bark, and
there remain until spring, changing to adults. See _b_, fig. 13. They
then gnaw through the bark, and emerge about June 1 to propagate their
species.
_Remedies._ Same as for flat-headed borer.
[Illustration: FIG. 12. Adult Round-headed Borer, greatly enlarged.]
[Illustration: FIG. 13. Larva and pupa of the Round-headed Borer.]
[Illustration: FIG. 14. _a_, Incision in which egg is deposited; _b_,
same, the wood has been split along line _a_; _e_, showing egg in place;
_c_, showing how egg is inserted under bark; _d_, egg greatly magnified;
_e_, hole through which adult emerged; _f_, channel of larva; _g_,
insect in pupal state just before issuing as an adult.]