The order Oniscidea contains various species of the woodlouse, also known as a doodlebug, pill bug, or sow bug. Some, notably the genus Armadillidium, can roll up into a ball if threatened.

Some common European species are Porcellio scaber (rough woodlouse) and Oniscus asellus (common woodlouse). One found in the southern US is Armadillidium vulgare (pill woodlouse).

Other names for the woodlouse :

armadillo bug

cheeselog

cheesey-bug

roly-poly

parson's pig

potato bug

roll up bug

slater

Hodidod

carpenter bug

wood Bug

pea bug

chuggy-peg and

chuggy-pig.

The woodlouse are isopods assigned to the suborder Oniscidea. There are over 3000 known species known by such names as the "roly-poly", "armadillo bug", "cheeselog", "doodlebug", "monkeypea", "pill bug", "potato bug", "roll up bug", "slater", and "sow bug".

The woodlouse is the only crustacean to occupy an inland habitat. Woodlouse body length is 11mm, which is rather small, never reaching more than three-quarters of an inch long, with oval shaped bodies, convex above, and empty beneath.

The two most common European woodlouses are Oniscus asellis, which has a brown body and yellow marks on its back, and Porcellio scaber that has mix blue and grey body. Both are rather flat.