Booklice are less than 1/8 inch long and creamy to grayish white. They resemble short termite workers. Species that infest indoor environments usually have no wings, but they do have legs and visible antennae. Their head is bulbous, and they have chewing mouthparts. There are many species of booklice, but for control purposes, it is not necessary to identify them to species.

Booklice are common outdoors in moist areas, beneath mulch, and in forested areas. They require significant humidity to survive, and they feed on mold. They have gradual metamorphosis, meaning the nymphs look similar to adults.

Booklice do not damage structures, paper, or fabric, but they feed on the mold that grows on these things when dampness supports the growth of mold. They may appear in bath- rooms, showers, around pipes that leak or sweat, or in water-damaged cabinets under sinks. They may become a nuisance in new construction when spackle is not dried thoroughly, leaving humidity that favors mold growth.