Psocoptera (/soʊˈkɒptərə/) are a paraphyletic group of insects that are commonly known as booklice, barklice or barkflies.

[9] They have chewing mandibles, and the central lobe of the maxilla is modified into a slender rod.

[11] They may festoon large sections of trunk and branches in dense swathes of silk.

[12] Some psocids have small ovipositors that are up to 1.5 times as long as the hindwings, and all four wings have a relatively simple venation pattern, with few cross-veins.

Some species are wingless and they are easily mistaken for bedbug nymphs and vice versa.

Besides damaging books, they also sometimes infest food storage areas, where they feed on dry, starchy materials.

[16] Psocids, among other arthropods, have been studied to develop new pest control techniques in food manufacturing.

One study found that modified atmospheres during packing (MAP) helped to control the reoccurrence of pests during the manufacturing process and prevented further infestation in the final products that go to consumers.

[20] Here is a cladogram showing the relationships within Psocodea, with the former grouping Psocoptera highlighted:[2] Phthiraptera Liposcelididae Pachytroctidae Sphaeropsocidae Amphientometae Psocomorpha Trogiomorpha