S. Mahunka szerk.: Folia Entomologica Hungarica 46/2. (Budapest, 1985)

dropping is "poisonous" for the pasture owing to its high nitrogen content; and, while the rapid enitrogenation is the most impontant process in the equilibrium of the pasture ecosystem, consequently the role of the diverse coprophagous dipteran populations is regarded as vitally important in this process. The most numerous populations among these obligate coprophagous species are those of Sepsis thoracica R.-D., seven more species of the family Sepsidae, nine species of the family Sphaeroceridae, but also the role of the populations of the bigger-bodied Paregle cinerella Fall, and that of the species Neomyia cornicina (with lower dominance but with large individual weight) can be rather significant. 4) The total dominance of the Haematobia species (here: H. irritans and H. titillans

) is so low (in Hungary 0.2-1.72 %, it is 0.9 % for the samples of the present series of investigations), that we can state unambigously: even a complete eradication of the populations of the Haematobia species would not affect the normal way of the decomposition of the cattle droppings. 5) As a consequence of the last two points, the application of any non-selective larvicide is highly hazardous and it is surely much more expensive and much less effective method than the control of the imagos of Haematobia species. The most effective control method against the Haematobia population is the spraying against the females - which would produce overwintering instars - in early autumn. 6) The larval populations of Musca autumnalis are the most important in the rapid decomposition of the cattle droppings on pastures in Hungary from the beginning of May till September. Though their dominance in the number of invividuals in dipteran larval populations is 7 to 25 % (in the samples from Mezohék this is 56 . 97 %), and the females of Musca autumnalis do not lay eggs evenly In space and in time, their mass-dominance is even higher, since e.g. a 10.03 % dominance in the number of larval individuals is equal of 56.74 % mas s-dominance (calculations based on data in PAPP (1971); the mass-dominance of Musca autumnalis larvae may exceed the value of 80 %. This is why nobody can exclude the harmful consequences of the complete eradication of Musca autumna lis larval populations to the rapid decomposition of the droppings in the summer. By all means, if one risks such a trial, its consequences have to be analyzed by contributions of microbiologists, coleopterologists, acarologists and dipterists; these latter contributors would study the possibility that the larval populations of obligate coprophagous species are or are not able to take over the role of the larval populations of M. autumnalis (at least partly). 7) Considering the previous point and our new data on the fraction of the actual imaginai populations of Musca autumnalis

, which is on the bodies of cattle at a given time (this is significantly lower than based on previous estimations, and namely only 0.1 to 0.5 %, keeping off this small fraction of the M. autumnalis imaginai populations from cattle seems a far more perspective method rather than an overall killing of these imagos. 8) Owing to their very low dominance, the populations of the Hydrotaea species are less important in Hungary than in the European countries with cooler climate but in full awareness of their lifehabits, the extension of their studies is necessary also here. The improvement of control methods and the development of reasonable control systems require a better consideration of the results of taxonomy (cf. PAPP, 1985). REFERENCES ARENDS, J.J., WRIGHT, R.E., LUSBY, K.S., and McNEW, R.W. (1982): Effect of face flies (Diptera: Muscidae) on weight gains and feed efficiency in beef heifers. - J. econ. Ent., 75(5): 794-797. ARENDS, J.J., BARTO, P.B. and WRIGHT, R.E. (1982): Transmission of Moraxella bovis in the laboratory by the face fly (Diptera: Muscidae). - J. econ. Ent., 75(5): 816-818. BALL, S.G. (1982): Seasonal distribution and host range of some stock-visiting Diptera. - In: Burgess, N.R.H., Port, G.R. and Titchener, R.N. (Eds): Ectoparasites of veterinary and medical importance in temperate areas, p. 49-52. CALDWELL, E.T.N, and WRIGHT, R.E. (1981): Observations on overwintering of the face fly, Musca autumnalis (Diptera: Muscidae) near Guelph, Ontario. - Proc. ent. Soc. Ontario, 112: 77-80. COOK, I.M. and SPAIN, A.V. (1982): The effects of temperature and moisture on survival of the immature stages of the buffalo fly, Haematobia irritans exigua de Meijere (Diptera: Muscidae). - Aust. J. Zool., 30: 923-930.