These insects are commonly known as barklice or booklice, and the name of the order derives from the Greek ‘psokos' meaning rubbed or gnawed and ‘ptero' meaning wings. There are about 3,200 known species, divided into 35 families, distributed worldwide. Psocids are 1 - 10 mm in body length, they have biting mouthparts and undergo simple metamorphosis; nymphs live with adults and pass through 6 instars before they reach maturity. All psocids have silk glands and some form large webs, in which the community lives. The habitat of psocids includes living or dead foliage, ground litter, bark of trees, and human habitations. Barklice are winged and live on tree trunks, branches and leaf litter, and feed on organic matter such as lichens, algae and dead plant and insect material. Booklice are wingless, less than 2 mm in size and live indoors, where they feed on stored grains, book bindings, wallpaper paste, fabric sizing, and other starchy products. They will also feed on collections of dried insect specimens. They may become a nuisance, but psocids are of little economic importance.