[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.

Like aphids, however, many psocids are parthenogenic, and the presence of males may even vary between different races of the same species.

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.

However, this is somewhat unclear, as analysis has shown that Psocodea could instead be the sister taxon to Holometabola, which would render Paraneoptera as paraphyletic.

[6] Here is a simple cladogram showing the traditional relationships with a monophyletic Paraneoptera:[6] Polyneoptera Holometabola Psocodea Thysanoptera (thrips) Hemiptera (true bugs) Here is an alternative cladogram showing Paraneoptera as paraphyletic, with Psocodea as sister taxon to Holometabola:[6] Polyneoptera Holometabola Psocodea Thysanoptera (thrips) Hemiptera (true bugs) Here is a cladogram showing the relationships within Psocodea:[3] Philopteridae Anoplura Rhynchophthirina Trichodectidae Amblycera Liposcelididae Pachytroctidae Sphaeropsocidae Amphientometae Homilopsocidea Caeciliusetae Psocetae Epipsocetae Philotarsetae Archipsocetae Atropetae Psyllipsocetae Prionoglaridetae (paraphyletic) The order Psocodea (formerly 'Psocoptera') is divided into three extant suborders.

They have two- or three-segmented tarsi, this condition being constant (e.g., Psocidae) or variable (e.g., Pseudocaeciliidae) within families.

Additional veins are found in some families and genera (Dicropsocus and Goja in Epipsocidae, many Calopsocidae, etc.)

Psocomorpha is the largest suborder of the Psocoptera sensu stricto (i.e., excluding Phthiraptera), with about 3,600 species in 24 families, ranging from the species-poor Bryopsocidae (2 spp.)