The testes are connected to the seminal vesicles by the vas deferens. There is no outstanding difference between the histology of the vas deferens and that of the seminal vesicles. The walls of these ducts consist of an inner layer of epithelial cells which is surrounded by a network of muscle fibers extending in various directions (Fig. 8a and b). In D. baccarum, as in many other Pentatomidae (Davis, 1955), the heads of the spermatozoa are embedded in the epithelial lining of the seminal vesicles and their tails extend posteriorly in a spiral into the lumen.