The adult, fig. 10, is flat, about three-eighths of an inch long, of a
greenish black with coppery reflections. They appear about the last of
May and deposit eggs from then until September. They generally lay their
eggs in a diseased portion of the tree, where it has been bruised, or
sun-scalded, or in trees of weak vitality, in bad health from lack of
cultivation or moisture, or from soil poverty. The eggs are small and
yellowish, and are found singly or in numbers in crevices in the bark.
The larva, or borer, fig. 11, when young, is yellowish, with a broad,
flat head; it soon bores to the sap-wood, where it feeds. At this time
it is easily discovered by the "castings" from the opening. As they
become older and larger they bore into the harder wood, making flattened
chambers. In about a year they gnaw a channel to the outside, excepting
a thin layer of bark, and backing a little way they crowd castings to
the front and change into the perfect insect, emerging about the last of
May.
[Illustration: FIG. 10. Adult Flat-headed Borer.]
[Illustration: FIG. 11. Larva of a Flat-headed Borer.]
_Remedies._ Keep the tree thrifty, free from bruises or sun-scald, and
the flow of sap will drown them. If any are detected by the castings,
cut in, and use a hooked wire to pull them out. Some washes will deter
the female from depositing eggs. For instance: Equal parts of soft soap
and sal soda, with enough crude carbolic acid to give a strong odor.
Apply with a brush several times in a season, especially where the bark
appears unhealthy.