Abstract: The invention relates to compounds of the general formula wherein Ar1, Ar2, R4, R5, R6, R7, R8, W, X, a and b have the significances given in the specification, and optionally the enantiomers thereof. The active ingredients have advantageous pesticidal properties. They are especially suitable for controlling parasites on warm-blooded animals.

Abstract: A device for dispensing a measured dose of liquid from an attached container which container has an elongate casing defining a dispensing cylinder, one end of the casing being adapted for mounting on the container. A plurality of dose indications are provided on the external surface of the casing so that a dose may be pre-selected by moving a dose setting collar along the casing. The collar has a stop engageable with a selected one of a multiplicity of recesses on the casing to secure the collar at the required position. A plunger having a piston co-operating with a cylinder defined by the casing is movable to lift the piston from said one end of the casing until the piston abuts the dose setting collar so charging the dispenser. Depression of the plunger to move the piston back to said one end dispenses the selected dose from an outlet port.