Nye & Fletcher (1991) stated:-
A different species, also from North America but in the Pyralidae, had earlier been named in a new genus and species on the corresponding page of the previous volume and had an almost identical binomen i.e. Eustixia pupula Hübner, 1823, ibidem 2: 24, currently accepted as its valid name. Ever since Barnes & McDunnough, 1917, Check List Lepid. boreal Am.: 184, the species in the Yponomeutidae has been known as Lactura pupula (Hübner, ).
If Eustixis Hübner, , is accepted as a nomenclaturally available name it is senior to and must be used instead of Lactura Walker, 1854. If Eustixis Hübner, , is treated as an incorrect subsequent spelling of Eustixia Hübner, 1823, the E. pupula Hübner, , is a primary homonym of Eustixis pupula Hübner, 1823, and must not be used as a valid name. To retain stability Eustixis should be treated as an unused senior synonym (for over 70 years) and a case for its conditional supression submitted to the Commission under the Code (Edn 3), Article 79(c).
The late J. Kyrki of Finland had informed us that he intended to transfer Eustixis to the Zygaenidae Phaudinae.
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