Synonymized with Haemorrhagia diffinis as a subspecies by Rothschild & Jordan, 1903, Novit. zool. 9 (suppl.): 449. Treated by Draudt, 1931, in Seitz (ed.), Die Gross-Schmett. Erde 6: 881, as a form of Haemorrhagia diffinis ariadne Hodges, 1971, in Dominick et al.Moths Amer. N. of Mexico 21: 117, downgraded thetis to a form of Hemaris diffinis. Treated as a subspecies of Hemaris diffinis by Bridges, 1993, Cat. Fam. Gen. Spec. Sphingidae of the World: VIII.9. Resynonymized with the nominotypical subspecies by Kitching & Cadiou, 2000, Hawkmoths of the world: 47. Reinstated as a species by Schmidt, 2009, J. Lepid. Soc. 63: 102.