These are small, pale brown to white insects less than 6mm long.  Wings may be present or absent, and they have a large swollen area above the mandibles.  Often they are found in books, on floor molding and in closets.  They do not suck blood, but feed on molds and mildews.
They are often called “hundred-leggers” and have one pair of legs per segment.  They are long (up to 6″) and wormlike.  The 40 to 50 body segments are flattened and the head has one pair of antennae.  Some species can bite and penetrate the skin with their mandibles.  Centipedes are beneficial outdoors, feeding on insects and other anthropods
They are small flies that breed in damp soil or decaying vegetable matter.  Often they are brought into houses in potted plants or are found in commercial buildings in planted areas.  Fungus gnat adults are attracted to light and often are found around windows.
They are often called “thousand-leggers” because they have many legs (two pairs per body segment).   They have many cylindrical body segments and one pair of short antennae with seven segments.  Millipedes feed on decaying organic matter and are found in decaying vegetation and mulched areas.  They are nocturnal and are known to have mass migrations form swampy area of Florida.
Silverfish are gray and their bodies are covered with scales.  They are about 3/4″ long.  In buildings they can feed on starch and fabric, often causing damage to book bindings.  Silverfish are active and hide during the day.  When objects under which they hide are moved, they dart about seeking a new hiding place.
Springtails are insects about 1mm to 2mm long.  They are white to grayish in color, with no wings.  They have a forked structure on the rear of the body that enables jumping.  Springtails live in mulch and wet soil, but can migrate into homes and swimming pools in large numbers.  They feed on molds and decaying vegetation.
Plaster bagworms are small caterpillars.  Each bagworm spins its own grayish case that is about the size and shape of a watermelon seed.  Plaster bagworms are common in garages and around windows.  They feed on spiderwebs and can destroy fabric in houses.