Abstract
The morphological features, especially those of instrumenta cibaria, genital opening, perivulvar pore, marginal dorsal duct, grand spine, of Pseudaulacaspis pentagona were examined with a scanning electron microscope. As a result, it could be demonstrated that each circumgenital pore consited of a great number of small pores showing each about ten mushroomlike projections. In addition, insertion of stylets in mulberry tissues was examined at each growing stage from hatching larva to female imago, and it was observed that the stylets penetrated into the phloem-parenchyma two hours after insertion, and thereafter they curved into the phloem and broke into annulation along the cambium. Moreover, the mode of insertion of the stylet as well as the morphology of the portion of mulberry tissues from which the scale sucks were examined with a light microscope. The influence of stylet penetration into the plant cell was also investigated. It was found that when the stylet penetrated into the plant cells, these were killed.
