thunderbolt beetle

Wiktionary

1. n. A long-horned beetle (Arhopalus fulminans) whose larva bores in the trunks of oak and chestnut trees.

GNU Webster's 1913

1. n. (Zoöl.) a long-horned beetle (Arhopalus fulminans) whose larva bores in the trunk of oak and chestnut trees. It is brownish and bluish-black, with W-shaped whitish or silvery markings on the elytra.