Insects and other arthropods with hard shells are typically characterized by an exoskeleton made of chitin. This exoskeleton provides protection and support to the organism.
Here are some bugs with hard shells:
Beetles
(Order: Coleoptera)
Beetles are the most diverse group of insects, and their most defining characteristic is their hard, chitinous elytra (hardened front wings that cover the more delicate hind wings and abdomen). As with all insects, beetles have six legs.
True Bugs
(Order: Hemiptera)
Many true bugs, like stink bugs and shield bugs, have a tough exoskeleton, though it’s not always as hard as the shell of a beetle. They are also insects and hence possess six legs.
Cockroaches
(Order: Blattodea)
Cockroaches have a hard, protective exoskeleton that they shed multiple times throughout their life as they grow. Cockroaches, being insects, have six legs.
Pillbugs and Sowbugs
(Order: Isopoda)
While these are not insects (they’re crustaceans), they are often mistaken for bugs and have a distinctive hard shell. Pillbugs are sometimes called “roly-polies” because they can roll into a tight ball. They have seven pairs of legs.
Cicadas
(Order: Hemiptera)
Cicadas have a tough exoskeleton, especially noticeable when they molt and leave their old exoskeleton behind. cicadas have six legs.
When considering bugs with hard shells, it’s important to note the difference between true insects and other arthropods. All insects are arthropods, but not all arthropods are insects. Some of the creatures listed above, like crabs and pillbugs, are arthropods but not insects.