An ethanol extract of Lactarius necator gave 3,8-oxa-13-hydroxy-lactar-6-en-5-oic acid gamma-lactone and furanether A, besides other known sesquiterpenes. Syntheses of these internal ethers, as well as the 13-oxa-lactonic analogue, were performed. The antifeedant properties of the internal ethers measured against the storage pests Tribolium confusum, Trogoderma granarium and Sitophylus granarius are reported.