is the outermost portion of the exoskeleton
of an insect
(and various other arthropods
); its exact composition and structure may differ somewhat among different taxa
, but certain aspects can be generalized:
- It is secreted by the epidermis, and is deposited on top of the procuticle via pores that pass outwards through the procuticle from the epidermal cells.
- It contains no chitin, and is itself arranged in layers.
- The layers typically consist of an inner epicuticle, an outer epicuticle (or cuticulin layer), a wax layer, and a cement layer.
- The wax layer is not present in all arthropods, as its primary function is to reduce water loss.
- The epicuticle cannot be digested during the molting cycle (see ecdysis), so it and the exocuticle are shed.