endocuticle

The endocuticle is the inner layer of a cuticle, specifically the colorless, flexible, and highly chitinized inner layer of an insect's exoskeleton. The cuticle itself is the outer layer of an organism that interacts with its environment. In arthropods, like insects, the epidermis secretes a tough cuticle primarily made of chitin fibers embedded in a protein matrix. This cuticle can be tough and flexible, or form rigid plates that create a true exoskeleton. The endocuticle is distinct from the epicuticle, which is the outermost layer of the cuticle. The exocuticle is an intermediate layer, sometimes considered the outer part of the endocuticle.1234