- Tiny, soft–bodied wingless, 1–3 mm long.
- New Zealand has two of largest known in world – giant 14 mm long
- Worldwide, with many native species
- Widespread in damp soil, common in leaf litter, sometimes massed on the surface of small pools of water
- Feed on micro–organisms – fungi, algae, bacteria, lichens. Others eat dead or live plant material and pollen
- Most have forked jumping tail enabling them to spring away from danger