Sometimes called “thousand-leggers”, commonly encountered millipedes can be as large as 4½” long and are usually brown or black. Many species protect themselves by secreting foul-smelling chemicals. They’re scavengers which feed mostly on decaying plant matter. Massive millipede migrations of hundreds or thousands sometimes occur, often as a result of heavy rains. They’re primarily a nuisance, but large numbers often require professional control.
Pillbugs and sowbugs are actually crustaceans, similar to shrimp and lobsters, that have adapted to living completely on land. About ⅝” long, they feed on decaying vegetation. They require high moisture to survive and quickly die as a result of water loss when they enter a home