Résumé : The results of a study of the decay of the Λ8Li and Λ12B hypernuclei are presented. The Λ8Li→π-+8Be*→π-+4He+4He and Λ12B→π- + 12C*→π-+4He+4He+4He modes have been investigated in detail. New information on the decay mechanism of the 16.11 MeV state of 12C has been obtained. © 1969.