The invention relates to substituted amidine compounds of formula (I), to the enantiomers, diastereomers and salts thereof and to compositions comprising such compounds. The invention also relates to the use of the substituted amidine compounds, of their salts or of compositions comprising them for combating animal pests. Furthermore the invention relates also to methods of applying such substituted amidine compounds. The substituted amidine compounds of the present invention are defined by formula (I) wherein A1 to A4, B1 to B3, R1 to R3, (R4)p, (R5)q, X and Y are defined as in the description.