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

The semiliquid substances of high nitrogen content of the cattle droppings, which are cementing the undigested macroscopic grass particles when dried, can pass more or less completely through the guts of dipterous larvae (and thus disintegrating) if the amount of larvae developing there is c. 5 % of the weight of cattle dropping (measurements in dry weights, see PAPP, 1971, 1976). According to our experiences, one-fourth to one-third of this amount (1.25-1.7 %) is sufficient to a rapid disintegration of the summer cattle droppings. If the larval populations of the obligate coprophagous species in lack of Musca autumnalis can rise to these values of production and only then - we can expect that the decomposition of cattle droppings will not be damaged. We reject the application of any non-selective larvicides on pastures categorically, as proposed e.g. in HALL and FOECHSE (1980), MILLER (1970), MILLER and GORDON (1973), MILLER and PICKENS(1975), MILLER (1974), MILLER and PICKENS (1975), MILLER et al. (1978), MILLER (1982), SCHMIDT (1983), etc. Taking any of the strategies, on thinking it over, we can declare now, that any control of Musca autumnalis is to be Judged on the basis of a thorough study of all the dipterous species developing in cattle droppings; this emphasizes again the importance of taxonomical studies of the populations of pasture flies (PAPP, 1985). Hydrotaea spp. and other secretophagous species On the basis of our earlier studies, of the data of Dr. Ferenc Mihályi, as well as on the findings of GREGOR and MINÁR (1980) we can say that at least 30 species of the family Muscidae alone are living in Hungary, which count as secretophagous species in the pastures. Besides the three common species of Musca

. the presence of four species of Hydrotaea (

H. albipuncta. H. ar- mlpes

, H. glabricula

, H. irritans

), Morellia simplex, Myospila medltabunda. Musca larvipara and Ravinia striata (latter one belongs to Sarcophagidae) have been proved In the pastures published in the three tables. We believe, that the biggest deficiency of our studies hitherto is that rather few specimens of Hydrotaea have been collected, and owing to their relative rareness, few specimens have been reared, though the importance of Hydrotaea irritans (HILLERTON et al., 1983,1984, and others) and of Hydrotaea armipes (DUSBÂBEKet al., 1982, GREGOR and DUSBÁBEK, 1982) the transmission of the diseases of cattle has been documented. Our studies have proved that Hydrotaea irritans is very rare in Hungary (except for forest or forest-edge pastures in our mountains), on the results of rearings we can state that the dominance of the other Hydrotaea species is also a low value. But since in all probability a large fraction of their imago populations are sucking fluids on the eyes, cheek and wounds of cattle, further and more extensive studies are necessary for surveying the role of various secretophagous species other than Musca autumnalis also in Hungary.The stock-breeding of Musca osiris founded in the Parasitological Department of the University of Veterinary Science, Budapest, may promote studies on those species, since the stock-breeding of that species is relatively easy, the individual number of Musca osiris on pastures is rather high, and there the males and females are attacking cattle in a high ratio and rather agressively. Conclusions 1) The actual size of the populations of the flies, which are pestering cattle on pastures and are developing in cattle droppings, and their true dominance cannot be estimated accurately on the basis of individual flies caught or counted on cattle or in their environs but only by rearing the imagos from droppings. 2) In the present series of investigations no more species (altogether 36 species) nor essentially different species-composition was found than in similar investigations in Hungary carried out earlier (Aranyosgadány/SW Hungary), 1969: 36 species, 21 species of them identical with those in the present series; 17 species of the 30 species which were published by Papp (1976) from six regions of the country are included again in the present 36 species). If the present results are compared with the dominance and species-composition published by Gregor and Miná? (1980), Ball (1982), Titchener et al. (1981), Hillerton et al. (1984) we can even more corroborate the principle (Papp, 1976: 137) that "the droppings have no uniform fauna independent of the geographical locality, even within the Palaearctic Region". This is true also for the species-composition and even more so for the dominance relationships of the dipterous species of veterinary importance (cf. Papp, 1985). 3) There are populations of numerous obligate coprophagous dipteran species in pastures of Hungary from spring till autumn, whose activity - since their imagos are feeding exclusively on dung - is purely beneficial in the decomposition of droppings. This is important to know, since every cattle