S. Mahunka szerk.: Folia Entomologica Hungarica 31/2. (Budapest, 1978)

cordance with the way of life of the species, therefore, it seems acceptable from evolutionary point of view, too. All three species have two intensive migration periods a year (BENEDEK and JÁSZAI, 1973). However, on hot days they often leave their living place. It depends on several factors partially unknown, that what will be the new biotope like they find and especially that how much and of what quality will be the food supply available. It will be very probably different from those in the original biotope. The advantage of omnivorous feeding habits is obvious at such a way of Life. The species mentioned often happen to migrate into periodic waters, fresh puddles, plashes where food supply especially of animal origin can be meagre. In such cases the euryecious, e.g. omnivorous species have an advantage (SCHÖNER, 1969). If we suppose that the three species investigated were accomodating to the environment also in feeding during their evolution, their feeding habits seem to be moved (to move) from the archaic predator (REEGERT, 1976) to omnivorous type. The facts mentioned above put the data of the respective literature in another light. The main cause of the contradictions must thus be that the majority of the authors have not considered in the desirable extent the possibility of omnivorous feeding habit. It is clearly imaginable that one of the species can be reared or even propagated under experimental conditions exclusively on foods of herbic or animal origin. However, the possibility of difference in feeding habits on specific or generic level is not precluded by this statement and inadequate identification seems to play a role in the development of contradictions. Acknowledgement: The author is deeply indebted to Dr. T. VÁSÁRHELYI for reading the manuscript and for his helpful criticism. REFERENCES BENEDEK, P. and JÁSZAI, V.E. (1973): On the migration of Corixidae (Heteroptera) based on light trap data - Acta Zool. Acad. Sei. Hung. 19: 1-9. BENWITZ, G. (1956): Der Kopf von Corixa punctata 111. (geoffroyi Leach) (Hemiptera-Heteroptera) - Zool. Jahrb. Abt. Anat. Ontog. Tiere 75: 311-378. BOROS, J. (1942): Haematologia. - Budapest: 1-369. DOSZTÁL,I. (1974): Comparative study of the water-bug (Hydrocorisae) populations of a deadarm of the Tisza and some sodic waters - Acta Biologica, Nova Series: 77-82. HORVÁTH, G. (1931): A Balaton vizében és viztükrén élő Hemipterák - Magy. Biol. Kut. Int. Munkái 4j^ 1-5. HUNGERFORD, H.B. (1919): The biology and ecology of aquatic and semiaquatic Hemiptera Univ. Kansas Sei. BuU. 11: 3-328. ISTOCK, C.A. (1973): Population characteristics of a species ensemble of water boatmen (Corixidae) - Ecology j)4: 535-544. JAMES, H.G. (1966): Insect predators of univoltine mosquitoes in woodland pools of the PreCambrian shield in Ontario - Canad. Ent. 98: 550-555. JANSSON, A. (1969): Identification of larval Corixidae (Heteroptera) of Northern Europe Ann. Zool. Fennici j6_: 289-312. JANSSON, A. and SCUDDER, G.G.E. (1972): Corixidae (Hemiptera) as predators: rearing on frozen brine shrimp - J. Ent. Soc. British Columbia ^9: 44-45. JORDAN, K.H.C. (1972): Handbuch der Zoologie. Heteroptera. BÜrlin: 1-113. KOSLUCHER, D. G. and MINSHALL, G.W. (19 73): Food habits of some benthic invertebrates in a northern cool-desert stream (Deep Creek, Curlew Valley, Idaho-Utah) - Trans. Amer. Micros. Soc. 92: 441-452. LINDBERG, H. (1944): Ökologisch-Geographische Untersuchungen zur Insektenfauna der Felsentümpel an der Küsten Finnlands - Acta Zool. Fennica 41: 1-178. MARTIN, N.A. (1970):The distribution and ecology of the Corixidae (Hemiptera-Heteroptera) in Leicestershire - Trans. Leicester Lit. Philos. Soc. j34: 101-118. MILLER, N.C.E. (1956): The biology of the Heteroptera. - London: 1-162. PAJUNEN, V.l. (1977): Population structure in rock-pool Corixids (Hemiptera, Corixidae) during the reproductive season - Ann. Zool. Fennici 14j 26-47.