Here, the genus is treated in the wide circumscription (sensu lato) adopted by many authors today, and represents the presumed core group of the Erechthiinae.

Other species of Erechthias were historically assigned to Acridotarsa – also of the Tineinae (E. deloneura) – or to Mesopherna of the Myrmecozelinae (E. epomadia).

E. glyphidaula has been a particular source of confusion; even veteran researcher Edward Meyrick, in some of his last works, no less than three times established a new monotypic genus for this species.

The enigmatic "genus" Acrocenotes – a single species initially held to belong to the Plutellidae, which are also not close relatives of Erechthias – is also included here in the present treatment.

[3] As another taxonomic curiosity of this genus, E. beeblebroxi is named after Douglas Adams's famous two-headed science fiction character Zaphod Beeblebrox;[4] the moth has a "false head" pattern that presumably helps to confuse would-be predators.