The document discusses the insect integument or exoskeleton. It is composed of three layers - the epidermis, basement membrane, and cuticle. The cuticle, which is ectodermal in origin, covers the entire exterior of the insect body as well as some internal structures. It provides structure, protection and lining. The cuticle itself contains two major parts - the non-chitinous epicuticle and the chitinous procuticle. Chitin, lipids, and polyphenols are the main constituents of the insect cuticle.