[The biology of the warble-fly oestromyia leporina Pallas 1778 (Diptera, Hypodermatidae), a parasite of the field-mouse Microtus arvalis Pall (author's transl)].

The present paper deals with the discovery of the warble-fly Oestromyia leporina in the surrounding of Giessen. The behaviour of the flies in the field is described; in particular the behaviour of both sexes before and during mating and of the female during the oviposition period is described for the first time. The relations between host and parasite are explained as well as the development from third-instar larvae into the puparaium and then into the imago. By further experiments it is attempted to find out the factors causing the long time of ten months' quiescence in the puparium. The range of hosts is tested by natural and experimental infections' furthermore it is discussed if the present findings can be applied to other populations of the same warble-flies in far-off regions.