Fine structure of the cuticle and structural changes occurring during moulting in the mite Tetranychus urticae. I: Fine structure of the cuticle

Structure of the cuticle of Tetranychus urticae (Acari, Tetranychidae) is described by means of electron microscopy. The cuticle is composed of an epicuticle and a lamellated procuticle. The epicuticle exhibits an inn er dense layer which shows a weak fibrillar appearence, a cuticulin layer, a wax layer and an outer cement layer. The procuticle can be differentiated in an outer exocuticle which extends to the ridges and lobes, characteristic of the cuticular surface, and an inner lamellated endocuticle. Lamellae are formed of helicoid arranged electron lucent microfibrils embedded in an electron dense matrix. Pores penetrate ali cuticular layers. Structure of the cuticle is compared to published information on the insect cuticle.