Characteristic features of this genus include: the lack of tegmina and of alae, a smooth pronotum with large, slightly wrinkled spines on its discus, and outwardly turned lateral paranotal lobes.[1]: 385
Carl Stål circumscribed Arulenus in 1877 for the species A. validispinus and A. punctatus, which Stål described in the same paper.[2] In 1887, Ignacio Bolívar transferred A. punctatus to its own, new genus Hirrius, giving it the name Hirrius punctatus.[3] Arulenus would be considered a monospecific genus until 2016 with Josip Skejo and Joy Honezza S. Caballero's description of Arulenus miae.[1]