Pesticides for the extermination of terrestrial arthropods are disclosed which comprise formulations of a combination of terpenes in aqueous solutions which may be used together with citral. No resistance to the formulations of the invention has been seen. When used on the scalp or body for lice infestation no extended dwell time is required. The formulations do not have unpleasant odors. The formulations are directed towards providing topical preparations which may be used on the skin, scalp and hairy body parts of humans and animals, sprays for use directly against terrestrial arthropods, a dipping solution for combs and a laundry additive, amongst others.