Trogiomorpha

Psocoptera () are a paraphyletic group of insects that are commonly known as booklice, barklice or barkflies. The name Psocoptera has been replaced with Psocodea in recent literature, with the inclusion of the former order Phthiraptera into Psocodea (as part of the suborder Troctomorpha).

They are often regarded as the most primitive of the paraneopterans. There are more than 5,500 species in 41 families in three suborders. Many of these species have only been described in the early twenty-first century. They range in size from 1–10 millimetres (1/32–13/32 in) in length.