Slugs and woodlice are the worst enemies of mushroom crops.
In external form Trilobites are not unlike Isopod Crustaceans, especially the terrestrial species commonly called "woodlice"; and until the nature of their appendages was known, it was thought by some authorities that the two groups might be related.
Wingless females of many tropical species present a close superficial resemblance to woodlice; and one interesting apterous form known as Pseudoglomeris, from the East Indies, is able to roll up like a millipede.
Like the woodlice they were capable of rolling themselves up into a ball, many specimens having been found fossilized in this state, with the pygidium pressed tightly against the head-shield.
CRUSTACEA, a very large division of the animal kingdom, comprising the familiar crabs, lobsters, crayfish, shrimps and prawns, the sandhoppers and woodlice, the strangely modified barnacles and the minute water-fleas.
A terrestrial habitat is less common, but the widely-distributed land Isopoda or woodlice and the land-crabs of tropical regions have solved the problem of adaptation to a subaerial life.
In some of the terrestrial Isopoda or woodlice (Oniscoidea) the abdominal appendages have ramified tubular invaginations of the integument, filled with air and resembling the tracheae of insects.
Aldrovandi in De animalibus insectis (1602) almost contemporaneously distinguished between "terrestrial insects," including woodlice, earthworms and slugs, and "aquatic insects," comprising annelids and starfishes.