Abstract:When wax insect (Ericerus pela) in its first instar fed in the leaf of Ligustrum lucidum, the tip of stylet reached the phloem of vascular bundle. The portion of the stylet in the leaf was 0. 10—0. 31 mm in length. The stylet might penetrate through living cells. The cells penetrated by styler exhibited no apparent reaction of injury. When wax insect in the second instar fed in branch, the tip of stylet fed in the functional sieve tube element. The fed sieve tube element also exhibited no reaction of serious injury. The length of the stylet portion in the bark was 0. 32—0. 75 mm. The penetration in the bark by a stylet was mainly intracellular, seldom intercellular. The stylet that pierced through the bark was encircled by a styler sheath of protein in nature. Branched stylet sheath was observed. At the position where the stylet sheath converged, the parenchyma cells exhibited apparent reaction of injury. The stytet might penetrate through many sieve tube elements, finally reached the newly-differentiated sieve tube elements. The results suggested that feeding of wax insect was a process of initiative choice. One year after collecting white wax by means of skinning instead of cutting the branch, the stylets and stylet sheaths still remained in the bark. Several layers of cells around them usually became necrotic. Stylets and styler sheaths in the outer cortex were surrounded by bending phellogen which separated them from the living cells. Many cyst-like structures were formed in the periderm. Such bark was no longer available for feeding.