Abstract: The present invention relates to a procedure for treating domestic animals and productive livestock belonging to the class of Mammalia (mammals) for systemic control of tissue-parasitic insect larvae of the order of Diptera, which comprises peroral administration, to the animals to be treated, of an effective dose of an active substance of the general formula I ##STR1## in which R.sub.1 is hydrogen, methyl, ethyl or cyclopropyl, R.sub.2 is hydrogen or methyl, R.sub.3 is hydrogen, methyl or cyclopropyl and R.sub.4 is hydrogen or methyl, or of an acid addition salt thereof which is non-toxic to mammals or of a composition which contains the active substance or an acid addition salt thereof which is non-toxic to mammals.

Abstract: The present invention relates to a procedure for treating domestic animals and productive livestock belonging to the class of Mammalia (mammals) for systemic control of tissue-parasitic insect larvae of the order of Diptera, which comprises parenteral or transcutaneous administration to the animals to be treated of an effective dose of an active substance of the general formula I ##STR1## in which R.sub.1 is hydrogen, methyl, ethyl or cyclopropyl, R.sub.2 is hydrogen or methyl, R.sub.3 is hydrogen, methyl or cyclopropyl and R.sub.4 is hydrogen or methyl, or of an an acid addition salt thereof which is non-toxic to mammals or of a composition which contains the active substance or an acid addition salt thereof which is non-toxic to mammals.