This invention relates to a method of treating myiasis of an animal by applying to the animal a composition comprising an parasiticidally effective amount of a compound of Formula 1, an N-oxide or a pharmaceutically or veterinarily acceptable salts salt thereof wherein R1 is Me, Cl, Br or F； R2 is F, Cl, Br, C1-C4 haloalkyl or C1-C4 haloalkoxy； R3 is F, Cl or Br； R4 is H； C1-C4 alkyl, C3-C4 alkenyl, C3-C4 alkynyl, C3-C5 cycloalkyl, or C4-C6 cycloalkylalkyl, each optionally substituted with one substituent selected from the group consisting of halogen, CN, SMe, S(O)Me, S(O)2Me, and OMe； R5 is H or Me； R6 is H, F or Cl； and R7 is H, F or Cl.
