Two new species of Thomisidae are described (Mecaphesa reddelli sp. nov. and Tmarus galapagosensis sp. nov.). Of a third species, Mecaphesa inclusa (Banks, 1902), three colour variations are described. Tmarus specimens previously listed from the islands have always erroneously been called T. stolzmanni Keyserling, 1880. The Philodromidae are mentioned for the first time for the archipelago and are represented by two new species: Apollophanes fitzroyi sp. nov. and Apollophanes (?) lonesome-georgei sp. nov.
New species, colour variation, Thomisidae, Philodromidae, island fauna.