Adult – 1/32"-1/8" long. They are shiny red-brown to black. The body is hairless, and lacks the general spider beetles characteristic restriction at the waist.
Lifecycle
Females lay up to 120 eggs either singly or in batches during early summer. The eggs hatch within 16 days, and remain in the larval stage for up to 6 weeks.
Adults emerge after 20-30 days of the pupal stage and may live for up to 12 months.
At the optimum temperature for development (33°C) it takes about 45 days for the life cycle to be complete.
Habits
Shiny spider beetles are tolerant of cool conditions and can stay alive for long periods without food.