R.J. TILLYARD (1907, Proc. Linn. Soc. NSW. 32: 394-399) described a second species of the Australian genus Diphlebia Sclys, as D. ”euphæoïdes”. TILLYARD adhered to this spelling elsewhere in this paper and in his later works, as did Y. SJOSTEDT to a corrected version, euphoeoides (1917, Ark. Zool. 11(11): 1-44). D.E. KIMMINS (1969, Bull. Br. Mus. nat. Hist. (Ent.) 23: 287-314), J.A.L. WATSON (1969, ./. Ausl. ent. Soc. 8: 153-160) and, most recently, C.A. BRIDGES (1991, Catalogue of the family-group, genus-group and species group names of the Odonata of the world. Bridges, Urbana). However, M.A. LIEFTINCK (1951, Am. Mus. Novit. 1488: 1-46) spelled the name euphaeoides, as did F.C, FR ASER (1960. A Handbook of the dragonflies of Australasia, R. Zool. Soc, N. S. W. Sydney), J.A.L. WATSON (1974, J Aust. ent. Soc. 13: 137-149), W.E. STEWART (1980, Aust. J. Zool. (Suppl.) 75: 1-72, D.A.L. DAVIES & P. TOBIN (1984, The dragonflies of the world: a systematic list of the extant species of Odonata, Vol. 1, Zygoptera, Anisozygoptera, S.I.O., Utrecht), S. TSUDA (1991, A distributional list of the world Odonata 1991, Tsuda, Osaka), W.W.K. HOUSTON & J.A.L. WATSON (1988, Zoological Catalogue of Australia, Vol. 6, Ephemeroptera, Megaloptera, Odonata, Plecoptera, Trichoptera, Austr. Gov. Pubi. Serv., Canberra), and J.A.L. WATSON, G. THEISCHINGER & H.M. ABBEY (1991, The Australian dragonflies, C.S.I.R.O., Canberra & Melbourne). C.A. BRIDGES (1991, ibid.) placed euphaeoides "Davies & Tobin” as an incorrect subsequent spelling and subjective synonym of euphæoides Tillyard. Which is the correct spelling? R.J. TILLYARD (1907, ibid.) wrote that "The specific name” (euphaeoides) "is adopted on the suggestion of M. Martin so as to maintain the uniformity of specific nomenclature in use for this genus” (p. 398). The only other species of Diphlebia then known was lestoides Selys, based on the generic name Lestes Leach 1815, which suggests that Tillyard based ” euphæoïdes” on the generic name Euphaea Selys 1840, and misspelled it.