Temporal range: Carboniferous–Recent
|Death's head cockroach|
Adult (above) and two immatures
In Exopterygotes the young resemble adults but have externally-developing wings. They undergo a modest change between immature and adult, without going through a pupal stage. The nymphs develop gradually into adults through a process of moulting.
They are distinguished from the Endopterygota (or Holometabola) by the way in which their wings develop. Endopterygota (meaning literally "internal winged forms") develop wings inside the body and undergo an elaborate metamorphosis involving a pupal stage. Exopterygota ("external winged forms") develop wings on the outside of their bodies without going through a true pupal stage, though a few have something resembling a pupa.