ABSTRACT This paper presents natural history observations on two species of the weevil genus Mononychus Germar (Coleoptera: Curculionidae) that feed on seeds of Iris L. in northeastern Turkey. The host plant of Mononychus schoenherrii Kolenati, 1859 is Iris iberica Hoffmann. Eggs are laid in seed capsules in which the larvae consume nearly all seeds in the capsule and pupate. Adults of the new generation emerge from the capsules and fly away for aestivation and hibernation. Mononychus punctumalbum (Herbst, 1784) develops on Iris spuria L. Similarly, eggs are laid in seed capsules in which a single larva consumes only two or three seeds, and later pupates in the capsule. New generation adults emerge from the seed capsules and hide in the soil litter for hibernation. Both species produce one generation per year.