Centipedes and Millipedes in Missouri Homes

Centipedes and millipedes are among the most common occasional invaders in Missouri homes — particularly in basements, bathrooms, and other damp areas. They are often confused with one another but are quite different animals with different habits and different significance to homeowners. Both are primarily outdoor arthropods that enter homes under specific conditions.

Centipedes: The Fast, Predatory One

Centipedes are predators — they hunt and eat insects, spiders, and other small invertebrates. Missouri's most common home-invading centipede is the house centipede (Scutigera coleoptrata), a distinctive and alarming-looking animal that many homeowners encounter in basements and bathrooms.

House Centipede Identification

• Long, flattened body, yellowish-gray with three dark stripes
• 15 pairs of very long legs that extend far beyond the body — adults have a leg span that can reach 3 inches
• Moves extremely fast — the sudden burst of speed when disturbed is what alarms most people
• Antennae as long as the legs

House centipedes do bite if handled, but bites from the common house centipede are generally minor — comparable to a bee sting, resolving quickly. They are not aggressive and bite only in self-defense when trapped against skin.

Why They Come Inside

House centipedes need moisture and prey. Homes with high humidity in basements and bathrooms, and with the insect populations that humidity supports, attract centipedes. Finding centipedes inside is often an indicator of two things: elevated moisture, and a supply of the insects they are eating. A centipede inside your basement is doing you a small service — it is eating other pest insects — but its presence suggests conditions worth addressing.

Millipedes: The Slow, Decomposer One

Millipedes are decomposers — they eat decaying plant material, not other animals. They are harmless to people and structures, though some species can release defensive chemicals that cause minor skin irritation if handled and then touching eyes or mouth.

Millipede Identification

• Cylindrical, worm-like body — unlike the flat centipede body
• Many short legs along the body length — two pairs per body segment (centipedes have one pair per segment)
• Moves slowly and steadily, often curling into a coil when disturbed
• Dark brown to black in most common Missouri species; some have reddish markings
• Most Missouri home-invading millipedes are 1 to 4 inches long

Why They Come Inside

Millipedes invade homes primarily during periods of weather stress — heavy rain that saturates their outdoor habitat drives them to seek drier conditions, and fall cooling prompts some movement indoors. They enter through foundation gaps, under doors, and through any low-level opening. They cannot survive long indoors — the lower humidity of heated homes desiccates them quickly, and they cannot find the decaying organic material they need to eat. The ones found dead inside simply dried out.

Control and Prevention

Both centipedes and millipedes are primarily controlled through habitat modification rather than direct chemical treatment:

• Reduce exterior moisture: Eliminate standing water, improve drainage, and reduce mulch or leaf litter adjacent to the foundation — this is the primary harborage for both
• Reduce indoor humidity: Dehumidify basements and crawlspaces; fix any water intrusion issues. Centipedes cannot survive in dry conditions.
• Seal entry points: Gaps under basement doors, around utility penetrations, and through foundation cracks
• Exterior perimeter treatment: Residual insecticide applied to the foundation perimeter kills centipedes and millipedes attempting to enter and reduces the populations adjacent to the home

Regular professional perimeter treatment as part of a general pest program significantly reduces both millipede and centipede intrusions as a natural side effect of the broader barrier application.