The invention relates to new isoxazoline compounds of formulawherein the variables have the meaning as indicated in the claims； in free form and in salt form； and optionally the enantiomers and geometrical isomers thereof. The compounds of formula (I) are useful in the control of parasites, in particular ectoparasites, in and on warm-blooded animals.本發明係關於呈自由形式及呈鹽形式的下式之新穎異唑啉化合物其中代號具有如申請專利範圍中所表明之含義；及視情況其對映異構體及幾何異構體。式(I)化合物適用於控制溫血動物體內及身上之寄生蟲，尤其是外寄生蟲。
