Borers
Description

Different types of borers have very different appearances. In general, there are round-headed borers (adults are long-horned beetles), flat-headed borers (adults are wood-boring beetles), and wood chewing caterpillars (adults are moth borers).
Please see this site for more information on descriptions.

Damage

Deposit eggs beneath bark, by piercing or chewing. Larvae feed by tunneling underneath bark. This may kill the tree.