Buprestid clamp in Cerceris fumipennis. (a, b) Ventral view of broadly concave median area of ventral fifth metasomal segment with an erect, cuticular process at the posterior margin acting as a brace (= buprestid clamp); (c) Ventrolateral view of buprestid clamp, showing the concavity (arrow) and brace; (d) Curved, in-flight posture of female Cerceris fumipennis using the buprestid clamp. Drawing by WGS.