Functional morphology of the sting apparatus of the spider wasp Cryptocheilus versicolor (Scopoli, 1763) (Hymenoptera: Pompilidae)

The females of the spider wasps (Hymenoptera: Pompilidae) hunt spiders to provision their larvae. The genital structures of pompilid females are modified in a sting that is used for paralyzing the prey (spiders) and defense. The skeleto‐muscular structure of the sting apparatus of a typical representative of the family (Cryptocheilus versicolor) is examined. The shape of sclerites, their relative positions and articulations are described. Some morphological adaptations are described for the first time. The wide anal arc of the tergum IX provides a stiff support for the muscles that move the valvulae. The resilin structures in the areas of articulation support the work of muscles and in some cases replace them. The 1st valvulae form a venom duct along their entire length, which provides the delivery of the venom to a specific point. An unpaired flap in the venom duct provides a dose of venom in the sting. This mechanism probably enhances the speed and accuracy of the wasp's sting movements. Functions of muscles and interactions of the structures of the sting apparatus of C. versicolor are discussed.