Ptinidae is a family of small to medium-sized beetles commonly known as spider beetles or deathwatch beetles. They are characterized by their oval-shaped bodies and long antennae. Ptinidae beetles are typically found in dark and damp environments, such as old buildings, where they feed on a variety of organic materials, including dead insects, fungi, and plant matter. Some species of Ptinidae are considered pests as they can infest stored food products and damage wooden structures.