Internal micromorphology of the frons plate in females of the oriental hornet

Scanning electron microscopy and energy dispersive x‐ray analysis (SEM/EDS) have been used to study the internal micromorphology of the frons plate in the Oriental hornet, Vespa orientalis . A conical shaped organ was described which is recessed into the frons plate and projects toward the interior of the acoustic box. The latter is located on the inner side of the frons plate. On the exterior of the conical region are observed aggregates containing Ca and Si, and a thin transparent membrane bearing a hole in its center. The innermost surface of the conical structure terminates bluntly as a convex lentiform tip, bearing a transparent oval‐shaped window in its center. The conical organ, excepting the window, is enclosed in several layers of epithelium. The structure of this many‐layered conical organ is highly complex; its numerous sub‐structures and the possible role as a gravity sense organ are discussed. © 1993 Wiley‐Liss, Inc.