Leaf-feeding caterpillars of Arachnis albescens Hampson, Caligo memnon Felder, Cermnidia butleri Moschler, Opsiphanes tamarindi Felder, and Sibine apicalis Dyar are pests of bananas in Costa Rica. Most of the time population densities of these insects are kept relatively low by natural enemies. The above-mentioned hosts were observed to be attacked by the following: A. albescens by Apanteles sp.; C. memnon by Ooencyrtus sp., Sarcophaga lambens Wiedemann, and Xenufens ruskini Girault; C. butleri by Achaetoneura aletiae (Riley), Anolas limifrons Cope, Apanteles sp., Brachymcria comitator (Walker), Carinodes sp., Elachertus sp., Entomophthora sp., Eriophora edax Blackwall, Eustala fuscovittata Keyserling, Gasteracantha cancriformes L. Macrocentrus sp. near koebelei Vierick, Meteorus laphygmae Vierick,, Microgaster sp., Thiodina Pseustes Chamberlin and Ive, and Trichogramma pretiosum Riley; O. tamarindi by A. aletiae , and Ooencyrtus submetallicus (Howard); and S. apiralis by A. aletiae, Apanteles sp., Casinaria sp., and Pelecystoma harrisinae (Ashmead).