Kalmar “genus” tana nufin matsayi na haraji da aka yi amfani da shi wajen rarrabuwar halittu. Rukunin nau'in nau'in nau'i ɗaya ne ko fiye waɗanda ke da halaye iri ɗaya da tarihin juyin halitta.Kalmar "Actias" ita ce jinsin asu a cikin dangin Saturniidae. Wannan jinsin ya ƙunshi nau'o'in nau'i daban-daban na manyan asu masu launi waɗanda aka fi sani da asu na wata. Halin halittar Actias ana samunsa da farko a Asiya, amma ana iya samun wasu nau'ikan a Arewacin Amurka.