An arthropodicidal composition comprising an arthropodicidally effective amount of an arthropodicidally active compound and a synergistically effective amount of at least one compound of the formula ##STR1## in which A is amino, alkylamino, dialkylamino or N-alkyl-N-arylamino, or an optionally substituted alkyl, alkenyl, alkoxy, alkenyloxy, alkylthio, aralkyl, aralkoxy, phenyl, phenoxy or phenylthio radical,R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 each independently is hydrogen, or an optionally halogen-substituted alkyl, alkenyl, alkoxyalkyl or alkylthioalkyl radical, or is halogen, nitro or dialkylaminoalkyl, or is optionally substituted phenyl or benzyl, or two of the radicals R.sup.1 to R.sup.8, together with the carbon atom or atoms to which they are bonded form an optionally substituted monocyclic or bicyclic ring andn and m each independently is 0 or 1.