Length 5-8 mm.
Once thought to be closely related to myriapods (centipedes), they are now under their own class Symphyla. They are tiny pale centipede-like creatures with long antennae. They have 15 body segments, and 11 to 12 pairs of legs on which they move very rapidly.
Very well adapted to life in the soil, they may go down to a depth of more than 50 cm. Population levels in cultivated land may be as much as 100 to 600 individulas per square metre. The adults may live for up to several years, and will go through various moulting stages. There are several different species and close scrutiny of the specimen under a microscope is required for correct identification.
They feed on dead and decaying plant material, and also on the roots and tubers of young seedlings, which can become quite a serious pest to gardeners and farmers.
Seen all year round, discovered in a variety of habitats, including gardens and greenhouses. Found in soil, leaf litter and under stones and logs. Common and widespread throughout Britain.