Fig. 14. Scheme of cooption of sutural ridges of two elytra in formation of the lock. (A) Transverse section across two closed elytra. Locks: FL, frictional to the metepisternum; SL, sutural clamp between elytra; SSL, subsutural click to the metanotum. (B) Parts of the sutural lock in closed elytra. (C) Direction of engagement by Fiori (1975). (D) Direction of engagement according to the present study.