consisting of halogen, for example fluorine and chlorine, (C.sub.1 -C.sub.4)alkyl, preferably methyl or ethyl, (C.sub.1 -C.sub.4)haloalkyl, preferably trifluoromethyl, (C.sub.1 -C.sub.4)alkoxy, preferably methoxy or ethoxy, (C.sub.1 -C.sub.4)haloalkoxy,