Unusual phenotypes of Leptotes pirithous (Linnaeus, 1767) were encountered on islands of the Cape Verde Archipelago in 2013 and 2017. Dark/pale and tailed/tailless forms of this polyommatine lycaenid species are illustrated and discussed. The name capverti Libert, Baliteau & Baliteau, 2011, is considered and the phenotype compared with dark forms elsewhere. It is concluded that many individuals are indistinguishable from the Indian Ocean f. insulana Aurivillius, 1909, and from other dark forms that occur in many localities. L. pirithous host-plants on eight different islands, and observations regarding phenotypes, are tabulated. The three specimens of Aurivillius’ insulana and the holotype and both paratypes of capverti are illustrated for the first time, together with a sample of specimens of L. pirithous from the African mainland, the Cape Verde Islands and other islands in the Atlantic and Indian Oceans.