(1) Previous records of natural enemies of the cacao thrips, Selenothrips rubrocinctus, Giard, are reviewed.(2) An account is given of the following natural enemies in Trinidad, B.W.I. :—Dasyscapus parvipennis, Franklinothrips tenuicornis, F. vespiformis, Chrysopids, Ninyas torvus, Termatophylidea maculata and Wasmannia auropunctata.(3) The Eulophid parasite, Dasyscapus parvipennis, was introduced into the West Indies from the Gold Coast in 1935. It is now successfully established in Trinidad, Puerto Rico and Jamaica, but has so far given no indication of economic control of the cacao thrips.(4) The importance of natural enemies is discussed. Observations are made on the feeding propensities of some of the predators in the laboratory. Chrysopids are regarded as the most important predators and probably exercise some measure of control.(5) Population counts of the cacao thrips and Chrysopid and Franklinothrips larvae are given.