bark beetle

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various small cylindrical beetles of the family Scolytidae that burrrow along the surface wood directly beneath the bark of trees, causing extensive damage.

Century Dictionary and Cyclopedia

1. n. A member of the coleopterous family Scolytidæ, nearly all of which make burrows between the bark and the wood of woody plants.
2. n. Xyleborus pyri, a scolytid beetle which perforates the bark of the apple and pear. Also called apple shot-borer.

Wiktionary

1. n. any of various beetles, of the subfamily Scolytinae, many of which reproduce in the inner bark of trees

GNU Webster's 1913

1. (Zoöl.) A small beetle of many species (family Scolytidæ), which in the larval state bores under or in the bark of trees, often doing great damage.

WordNet 3.0

1. n. small beetle that bores tunnels in the bark and wood of trees; related to weevils