Controllers ectoparasitic insect pest on animals and their use.

Use of a hydrazine derivative represented by the following general formula (I); wherein A represents (in this formula, R4 represents a hydrogen atom; X which may be the same or different represents one to five substituents selected from the group consisting of the C1-6 haloalkyl group); R1, R2 and R3 represent a hydrogen atom; Y represents one to five substituents selected from the group consisting of a cyano group; Z represents a C1-6 haloalkoxy group; and W represents an oxygen atom for the preparation of a composition for controlling ectoparasitic insect pests on animals.