Abstract
Arrestants which keep A. kariyai in the host habitat were isolated from the exuviae of the host larvae and their structures were elucidated by a combination of MS, PMR and CMR spectra. The chemical structurs of the arrestants were found to be a series of 2, 5-dialkyl-tetrahydrofurans. Impregnation of 0.1μg of each arrestant onto a paper disc elicited 70-90% response from A. kariyai.