Flattened, with one pair of legs on most of their segments; segments number 10 to 100; 1 to 1-1/2 inches long; various colors. Usually live outdoors beneath damp accumulations of leaves, stones, boards, etc. Occasionally find their way into homes, where they hide in moist basements, damp closets and bathrooms; when disturbed, they run swiftly. Feed on insects and spiders. Some species live as long as 5 to 6 years. Large jaws can inject poison, but a bite is comparable to a wasp sting, and is not life-threating.