Pill bugs" or "sow bugs", often found under rocks and logs in moist places, have the ability to roll up into a ball when disturbed. sow bugs are really crustaceans, not insects. therefore, sow bugs do not have
They do not have a distinct head and thorax but a fused version of the two called a cephalothorax. That's one of the major differences between insects and crustaceans, both being subgroups of arthropods.
