S. Mahunka szerk.: Folia Entomologica Hungarica 59. (Budapest, 1998)

The proportion of the body-size of the nymphas to the adult individuals is 1 to 1.5. The partial fusion of the dorsal rings begins in this period of development. Different organs than those of the imagos were not found. We could not identify the grubs and the nymphas on the basis of the morphological features whether they fall under the summer or the winter forms. The morphological differences of the protogyn and the deutogyn forms Some morphological differences were found among the size of Aculus schlechtendali. The body of the deutogyn female is bigger, its appearance is more robust. The protogyn form is shorter and slimmer (Fig. 2). The distance between the basal warts of the lateral setae is much wider in the winter individuals, but there is not any difference in the distance between the ventral setae. The frontal extension, the lateral, the ventral and the tailsetae are also longer; the number of the tergites is higher. According to our observations the changes of the length of the winter forms are not always accompained by the increase of the number of the tergites. A probable reason for the bigger size of the deutogyn individuals is the quantity of food-substance accumulated for hibernation. The separation of the imagos on the basis of the morphological characters is very difficult. Important deviations are in the external appearance within the species and the single forms. The length of the body, the solenidia, the setae and the prodorsum; the shape and the colour of the body; the number of the tergites are very different. (The results about the morphology of Aculus schlechtendali and the déviances of the two forms are seen in Tabie 1.) REFERENCES Boczek, J. and Kozlowski, J. (1985): Variation among offspring of one female Aculus schlechtendali Nalepa (Acari: Eriophyidae ). - International Journal of Acarology, 11.3: 151-155. Easterbrook, M. A. (1979): The life history of the eriophyid mite Aculus schlechtendali on apple in South-east England. - Ann. Appl. Biol, 91: 287-296. Easterbrook, M. A. (1984): The biology and control of the apple rust mite Aculus schlechtendali and Epitrimerus pyri on apple and pear in England. - In: Griffiths, D. A. and Bowman, C. E. (eds): Acarology VI. Ellis Horwood L. Chichester, 2: 797-805. Farkas, H. (1966): Gubacsatkák - Eriphyidae. - Magyarország Állatvilága. (Fauna Hungarie)., 18: 164. Gólya, G. and Kozma, E. (1997): Az almástermésűek levélatkájának életmódjáról és kártételéről. - Gyakorlati Agrofórum, 8. 9: 56. Herbert, H. J. (1974): Notes on the biology of the apple rust mite Aculus schlechtendali (Prostigmata: Eriophydae ) and its density on several cultivars of apple in Nova Scotia. - Can. Entomol, 106: 1035-1038. Authors' address: G. GÓLYA and E. KOZMA University of Agricultural Sciences Department of Plant Protection 2100, Gödöllő HUNGARY