[1]Walker, F. (1853) List of the specimens of neuropterous insects in the collection of the British Museum. Part II (Sialidae--Nemopterides). British Museum, London. pp. 193–476.
[2]McLachlan, R. (1873) An attempt towards a systematic classification of the family Ascalaphidae. Journal of the Linnean Society of London, Zoology, 11: 219-276.
[3]van der Weele, H.W. (1908) Ascalaphiden. Collections Zoologiques du Baron Edm. de Selys Longchamps. Catalogue Systématique et Descriptif, 8:1-326.

In 1853, Francis Walker described the hornfly as four independent species: Ascalaphus anticus, Ascalaphus longus, Ascalaphus loquax and Ascalaphus trux according to the wing color and body color (the color of the specimen varies according to the degree of corruption). Ascalaphus trux is regarded as a member of the Acheron group (Acheron group Lefébvre, 1842), and their model origins are all in Bangladesh.

Twenty years after Walker’s publication, Robert McLachlan (1873) [1871?] made a reasonable revision of these four "species" through comparative morphological analysis: Acheron was regarded as a genus-level unit, The four ceratophytes published by Walker are regarded as one species, and Acheron longus is designated as the effective name of the species, and Ascalaphus anticus, Ascalaphus loquax, and Ascalaphus trux are all used as the sub-synonyms of the species.

Herman Willem van der Weele (1908) revised this genus and made almost the same treatment as McLachlan (even citing McLachlan's treatment). Only Acheron trux was designated as the effective name of this species, and "longus" was used as one of the sub-synonyms.

According to Article 24 of the "International Animal Nomenclature Regulations": When multiple synonymous names are established at the same time, and the priority status of these synonymous names cannot be objectively determined, the priority will be published by the first one after another. The authors quoted these names in their works and selected from them fixed by the author, that is, select one of the species name to determine its priority (this author is called the "First Reviser"), in the first revision The species names selected by the subsequent revisionists shall be deemed invalid after the handling by the author.

Obviously, McLachlan was the first revision of the this species, so the effective name of this species should be "Acheron longus (Walker, 1853)".