 More recently, it has been suspected that the Western cicada killer ("S. grandis") represents more than one species.There is also evidence to suggest that either the Eastern cicada killer ("S. speciosus") has a subspecies or closely related species that mimics the Pacific cicada killer ("S. convallis").Alternatively, when they were already well distinct species, significant hybridization has occurred between them, though not enough to fully overcome their reproductive isolation.