Zmienność gruczołów grzbietowo-brzeżnych u larw II stadium i samic Lecanium corni Bouché z Taxus baccata L.

Abstract

A discription is given of the position of the dorsal-marginal glands (sub-marginal tubercles) in larvae in the second stage and females of the Brown Scale Insect (Lecanium corni Bouché). There are usually five pairs of these glands in the second stage larvae and nine pairs in the females. In both evolutionnal stages, however, a significant variability in the occurrence of these glands was observed, affecting the number and position of the glands on the body of the larva and the adult female. Various combinations of the distribution of the glands are given, and it is pointed out that the diagnostic feature hitherto considered as of primary importance cannot be accepted unconditionally.