Flat Bark Beetles - Cucujidae

The Cucujidae are mostly small, elongate, flattened insects with broad, prominent heads. Most members of this family feed on small animals they find under the bark of trees, usually beeches, maples, elms, ashes, and poplars. Their flattened shape allows these beetles to follow their prey into narrow cracks and crevices.

Flat bark beetles are usually dull in color One notable exception is Cucujus cinnabe:

inus, a brilliant red beetle that is somewhat larger than most other members of the family. Other members of the Cucujidae, Laemophloeus ferrugineus and L. minutus, for example, are sometimes found in food warehouses. These cucujids are smaller and less colorful, than the outdoor variety, and it is doubtful whether they actually damage stored foods.