Emsleyfolium diasae n. gen. et n. sp., from the Brazilian, Colombian, Ecuadorian and Peruvian Amazon is described in this contribution. This new genus is morphologically very similar to Stilpnochlora, but is distinguished from the other Steirodiontini genera by its cone-head (similar to some genera of subfamily Conocephalinae, e.g. Neoconocephalus and Bucrates), modification of the tenth tergite into three lobes and absence of styles on subgenital plate. Thanatosis behavior is described as a defense mechanism.