Compounds of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are independently lower alkyl having from 1 to 4 carbon atoms; and R.sup.3 is lower alkyl having from 1 to 6 carbon atoms, lower cycloalkyl having from 3 to 6 carbon atoms optionally substituted with methyl or ethyl, lower alkoxyalkyl having up to a total of 8 carbon atoms or lower alkylthioalkyl having up to a total of 8 carbon atoms are insecticidal.