Electron microscopic studies on the palpi of Cybister fimbriolatus fimbriolatus (Say)

Summary The maxillary palpi of the predaceous diving beetle Cybister fimbriolatus fimbriolatus Say were observed by transmission and scanning electron microscopy. Scanning electron microscopy shows at least two types of sensilla at the tip of palp, which are referred to as circumvallate and naked sensilla. The former are innervated with outer segments of distal processes of sensory cells, but the latter are provided only with chitin and cuticular substances.This work was supported by Grant NB 04687 from the National Institutes of Health of the United States of America.We wish to express our gratitude to Prof. H. Stanley Bennett, Laboratories for Reproductive Biology, School of Medicine, University of North Carolina, Prof. G. Yasuzumi, Electron Microscope Research Laboratory, Department of Anatomy, Nara Medical University, and Prof. John E. Bardach, Department of Wildlife and Fisheries, School of Natural Resources, University of Michigan, for their valuable advice to the present work.