Disclosed is a method of controlling ectoparasites that infest companion and livestock animals by applying to the animal an effective amount of 4-tert-butylphenethyl quinazolin-4-yl ether or 4-chloro-5-ethyl-2-methyl-N-[(4-tert-butylphenyl)methyl]pyrazole-3-carboxamide or 5-chloro-N-[2-[4-(2-ethoxyethyl)-2,3-dimethylphenoxy]ethyl]-6-ethyl-4-pyrimidinamine or 4-chloro-3-ethyl-1-methyl-N-[4-(p-tolyloxy)benzyl]pyrazole-5-carboxamide.
