Different morphological types of B-chromosomes in Rhinocola aceris from Katowice (southern Poland) were found for the first time in Psylloidea. Four types of supernumerary chromosomes: B1, B2, B3, and B4 were described on the basis of their morphology and heterochromatin pattern. Their behaviour during meiosis suggests a high tolerance of this species for different numbers of B-chromosomes.
A. Maryanska-Nadachowska, Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland