[The inhibition of metamorphosis inAeshna cyanea Müll. (Insecta: Odonata) by a juvenile hormone-mimicking compound].

The injection of farnesyl methyl ether into last instar larvae results in preventing metamorphosis completely (production of a supernumerary larva) or partially (production of adultoids). The degree of this inhibition depends on both dose and moment of injection of the juvenile hormone-mimicking compound. A critical period beyond which the injection will be without effect on the larvae was determined.The external morphology of several organs (mask, wing sheaths, legs, tergites and anal appendages) will be described, on supernumerary larva as well as on different types of adultoids. All these organs show various degrees of sensitivity to injected juvenile hormone-mimicking substance.These results are discussed on the basis of both "prothoracotropic" and juvenile hormone activity of farnesyl methyl ether.