Centipedes and millipedes are not insects because they have more than six legs, but they are closely related invertebrates. When outdoors, these invertebrates are innocuous organisms, but they may be considered pests when they share living space with us. Both of these groups of invertebrates have long, segmented bodies with either one pair (centipedes) or two pairs (millipedes) of legs on each segment. Their food preferences vary greatly.
Millipedes are similar to centipedes, but have two pairs of legs per body segment. Some people mistakenly refer to them as wireworms. (Wireworms are the larval stage of a beetle that feeds on roots of plants.) Millipedes are usually brown to blackish in color. The elongated body is rounded, no flattened, and they have no poison claws or legs. They usually coil up when disturbed, similar to the behavior exhibited by sowbugs or pillbugs (a related invertebrate).
Legs on a Millipede:
Millipedes are sometimes called thousand-legged worms because of their many legs. Millipedes are usually restricted to moist places where they feed on organic matter. In the fall, they may become a nuisance because they migrate away from feeding areas and invade homes. Because they crawl along the ground, they are usually found in lower floors and basements. Once inside the home, they usually die due to desiccation, although in moist basements, they can survive longer.
Millipedes live in organic matter (leaves, mulch, piles of wood or wood chips) and other material close to the house. Overmulching and/or overwatering in the garden can result in millipede attack on vegetable plants. Removing the organic debris or mulch materials near your home will help reduce the potential for invading millipedes.
To Discourage Millipedes Near the House:
Remove mulch and dead vegetation adjacent to the house. The safest and most environmentally sound way to control millipedes and centipedes already in the house is to step on them and vacuum or sweep them up.
Damp hiding places can be treated with indoor insecticides labeled for this use. Be sure to read and follow label directions when using any insecticides.