Iolaus silas, the southern sapphire, is a butterfly of the family Lycaenidae which is endemic to South Africa.
It occurs from the southeastern Nama Karoo in the Eastern Cape (Somerset East and Bedford areas), and along the eastern littoral to northern KwaZulu-Natal.[1] It is present in spekboomveld, coastal savannah and lowland forest.
The wingspan is 32–37 mm for males and 34–41 mm for females. Adults are on wing year round in warmer areas and from September to January in the southern part of its range.[1] The larvae feed on various mistletoes, namely Moquiniella rubra, Erianthemum dregei and Loranthus usuiensis.