exuvium

The old exoskeleton is referred to as an "exuvium" (or exuvia).

The pupa develops inside the exuvium of the last larval stage, a feature common to all Stratiomyomorpha.

In Latin it was Leonis exuvium super asinum.

The pupation within the larval exuvium constitutes a case of evolutionary convergence with Cyclorrhapha , in which group there is the formation of a true puparium .

Once the pharate adult has eclosed from the pupa, the empty pupal exoskeleton is called an "exuvium" (or exuvia); in most hymenopterans (ants, bees and wasps) the exuvium is so thin and membranous that it becomes "crumpled" as it is shed.