Compounds of formula I wherein X is O or S(.dbd.O).sub.n; n is 0, 1 or 2; R.sup.1 is optionally substituted alkyl, haloalkyl, alkenyl, haloalkenyl, alkynyl, haloalkynyl, cycloalkyl, halocycloalkyl, cycloalkenyl, halocycloalkenyl, phenyl, hetaryl, phenylalkyl, hetaryl alkyl, optionally fused to phenyl, hetaryl or heterocyclyl; A is --NR.sup.b.sub.2, --C(=G)GR.sup.b, --C(=G)NR.sup.b.sub.2, --C(.dbd.NOR.sup.b)R.sup.b, C(=G)[N.dbd.SR.sup.b.sub.2], --C(=G)NR.sup.b--NR.sup.2, C.sub.2-C.sub.6-alkandiyl, C.sub.2-C.sub.6-alkenediyl, C.sub.1-C.sub.3-alkyl-G-C.sub.1-C.sub.3-alkyl, wherein R.sup.b is as defined in the description, or optionally substituted phenyl, hetaryl, heterocyclyl, optionally fused to phenyl or heterocyclyl; B is an optionally substituted saturated or partially unsaturated hydrocarbon chain with 1 to 3 carbon chain atoms; D is an optionally substituted saturated or partially unsaturated hydrocarbon chain with 1 to 5 carbon chain atoms or C.sub.3-C.sub.6-cycloalkyl; G is oxygen or sulfur; or the enantiomers or diastereomers or salts or N-oxides thereof, processes for preparing the compounds I, pesticidal compositions and synergistic mixtures comprising compounds I, methods for the control of insects, acarids or nematodes by contacting the pests or their food supply, habitat or breeding grounds with a pesticidally effective amount of compounds formula I, and a method for treating, controlling, preventing or protecting animals against infestation or infection by parasites which comprises orally, topically or parenterally administering or applying to the animals a parasiticidally effective amount of compounds of formula I. ##STR00001##