Psocoptera

Psocoptera are an order of winged insects that are commonly known as booklice, barklice or barkflies. They first appeared in the Permian period, 295–248 million years ago. They are often regarded as the most primitive of the hemipterans. Their name originates from the Greek word psokos meaning gnawed or rubbed and ptera meaning wings. There are more than 5,500 species in 41 families in three suborders. Many of these species have only been described in recent years.

Psocoptera Temporal range: Early Permian – Recent
adult barklouse
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Superorder:	Psocodea
Order:	Psocoptera
Suborders
Trogiomorpha (7 families) Troctomorpha (9 families) Psocomorpha (24 families)

They range in size from 1–10 millimeters (0.04–0.4 in) in length.