The compounds 1-trifluoromethylthio-3,3-dimethyl-2, butanone-O-methylcarbamoyloxime and 1-difluoromethylthio-3,3-dimethyl-2-butanone-O-methylcarbamoyloxime are prepared from certain novel ketone and oxime intermediates. These compounds have insecticidal activity and are particularly effective against the Western and Northern corn rootworms, Diabrotica virgifera and Diabrotica longicornis respectively.