ABSTRACTFour new species of the hyphomycete genusGibellula, collected in South America and parasitizing spiders are described.G. mainsiiis characterized by mononematous, smooth-walled conidiophores.G. brunneahas typical brown conidiophores borne on bulbiform synnemata and aGranulomanussynanamorph which is produced on well-differentiated conidiophores.G. clavatawith its teleomorphTorrubiella clavatan. sp. resemblesG. leiopusbut has distinctive clavate, paired synnemata. Both stages were regularly collected in cacao plantations in western Ecuador.G. mirabilishas golden yellow paired synnemata with short conidiophores producing fusiform conidia. BothG. clavataandG. mirabilishaveGranulomanussynanamorphs. A dichotomous key to the new and accepted taxa is provided.