What is one of the only crustaceans that live their entire lives on land?

The Roly Poly or Pill bug as they are commonly called are members of a group of crustaceans called wood lice. Their scientific genus name is Armadillidium. The members of this group are the only crustaceans that do not have an aquatic stage in their life cycle. Like all crustaceans they breathe with gills and therefore must remain in damp places. They live in the leaf litter and under damp rotting wood. They are very helpful to the environment because they transform leaf litter and rotting wood into compost. They also eat many harmful fungi that grow on decaying matter. Roly polies live in groups and there may sometimes be individuals of various ages in the colony. The female has a brood pouch on her underside where she carries the eggs until they hatch and the newly hatched babies for up to two months. They may live as long as 3 years as adults. They generally hunt for food at night or heavily overcast days when the sky is really dark. They can be found by turning over rocks, debris in your yard, old rotting wood, and under damp leaf litter. These invertebrates make good terrarium animals if they are kept moist and are given lots of decaying matter to eat.