- Epicuticle
The epicuticle is the outermost portion of the
exoskeleton of aninsect (and various otherarthropod s); its exact composition and structure may differ somewhat among differenttaxa , but certain aspects can be generalized:
* It is secreted by the epidermis, and is deposited on top of theprocuticle via pores that pass outwards through the procuticle from the epidermal cells.
* It contains nochitin , 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 (seeecdysis ), so it and the exocuticle are shed.
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