A simple synthesis of beta-acaridial [(E)-1], the active principle of the sex, alarm and aggregation pheromone among astigmatid mites, was achieved in 5 steps from 1,2,4-butanetriol 2 in a 19% overall yield. Its analog, beta-acariolal 8, was also prepared in a 63% yield by oxidation of the intermediate, beta-acaridiol [(E)-7], with pyridinium dichromate (PDC). This synthetic route also gave beta-(Z)-acaridiol [(Z)-7] by using a Z-selective base in the Wittig reaction. (Z)-7 was oxidized to give a new monoterpene, beta-(Z)-acaridial [(Z)-1], which was detected as a trace component in the secretion of Caloglyphus polyphyllae, together with 8.