Psocoptera Click to enlarge image
Psocid (Order Psocoptera) Image: Andrew Howells
© Australian Museum

Psocids, sometimes known as 'booklice, belong to the Order Order Psocoptera.

What do psocids look like?


  • Less than 1 mm - 10 mm in length, but most are shorter than 5 mm.


  • Ovoid or abdomen swollen making it look like a lopsided dumb-bell;
  • Some flattened as if pressed from above;
  • Front of head bulges like a big round nose;
  • Appears soft and fragile.


  • Thread-like, usually longer than half their body length.


  • Small to large, prominent and well separated.


  • For chewing or munching; held downwards at rest.


  • Two (males only) pairs if present.
  • Both pairs membranous and clear,
  • Forewing usually wider and longer than hindwing.
  • Forewing venation simple, few cross-veins forming inconsistent shaped cells, with 'S-shaped' veins.
  • Wings usually extend beyond abdomen but some species have shortened wings.
  • At rest, wings held tent-like over body; hindwing hidden.


  • Six legs, short and stocky.

Abdomen tip:

  • Cerci (tails) absent.

Where are psocids and booklice found?

  • On or under vegetation, bark, rocks or leaf litter.
  • Some are found in houses such as booklice.

What do psocids and booklice do?

  • They are solitary or group together (eg. some species of Myopsocus).
  • When disturbed they run or fly away.
  • They are weak fliers, flying for short bursts then landing soon after. They primarily graze on microflora such as algae, lichens, and fungi and bits of plant or insect debris. They are an important group for breaking down microflora into units useful for other organisms in the food web.
  • They are active during the day.

What looks similar?

  • Psyllids can be separated from psocids by a number of features including: they often have large bulbous backward-pointing spines on hindcoxae ('thighs'); frontal region of head is divided vertically, so there are two halves of the facial region; first segment of antennae that attaches to head is enlarged and shaped like a doughnut; they jump when disturbed instead of running or flying.
  • Waxy-wings are a group of lacewings that do not have obvious forking of their wing veins. They can be distinguished from psocids as their wing veins are nearly straight or if bent curve in one direction only and their antennae are bead-like.
  • Springtails can be mistaken for psocids. They can be distinguished by a lack of wings and obvious mouthparts, a forked springing organ from tip of abdomen or if the organ is not obvious a siphon tube arising from their 'chest'. They also jump when disturbed.