148 Bulletin of Zoological Nomenclature 52(2) June 1995 Case 2903 Tropidoptei-a Ancey, 1889 (Mollusca, Gastropoda): proposed designation of Endodonta wesleyi Sykes, 1896 as the type species Neal L. Evenhuis & Robert H. Cowie Bishop Museum. P.O. Bo.x 19000-A. Honolulu. Hawaii 96817-0916. U.S.A. Abstract. The purpose of this appHcation is to conserve the original concept and subsequent understanding of the name Trupidoptera Ancey, 1889 for a genus of terrestrial gastropods belonging to the endemic Hawaiian family amastridae. The nominal species Helix alaia Pfeiffer, 1856 was fixed as the type, but this was based on a misidentification and it is proposed that the taxon actually involved be designated as type species; this is Endodonta (Pterodi.scus) wesleyi Sykes, 1896. Keywords. Nomenclature; taxonomy; Gastropoda; Tropidoptera; Pterodiscus; Hawaii. 1. Ancey (1889, p. 191) established the genus Tropidoptera for the single nominal species Helix alaia Pfeiffer. 1856 (p. 33), which is thus the type species by monotypy. Pilsbry (1893, p. 36) introduced the new name Pterodiscus as a replacement for Tropidoptera Ancey, 1 889, incorrectly considering Tropidoptera to be preoccupied by Tropidopterus Agassiz, 1846 (p. 167) in the Coleoptera. Pilsbry mentioned that Helix akita Pfeiffer was the type species and illustrated (pi. 4, fig. 44) what he supposed to be H. alata. 2. Tropidoptera Ancey, 1889 belongs to the endemic Hawaiian Island family AMASTRIDAE. Pilsbry (1893, p. 36) treated it (under the replacement name Pterodiscus) as a section of Cliaropa Martens, I860, the latter at that time a subgenus of Endodonta Albers, 1850 (endodontidae). Sykes (1896, p. 127) treated Pterodiscus as a subgenus of Endodonta. but later (1900, p. 292) regarded it as an independent genus in the endodontidae. Pilsbry & Vanatta (1905, p. 572) transferred Pterodiscus to the ACHATINELLIDAE, close to their new 'section' Helicamastra Pilsbry & Vanatta. 1905 (p. 570) of the genus Amastra Adams & Adams, 1855. The type species of Helicamastra is Amastra (Helicamastra) discus Pilsbry & Vanatta, 1905 (p. 571). 3. Sykes (1896, p. 127), having examined the type specimen of Helix alata Pfeiffer (see Hyatt & Pilsbry, 191 1, p. 121), pointed out that the 'Helix alata' of both Ancey (1889) and Pilsbry (1893) did not match Helix alata Pfeiffer. Sykes therefore proposed the new name Endodonta (Pterodiscus) wesleyi for the specimens identified as Helix alata by Ancey and by Pilsbry. 4. As mentioned in para. 2 above, Pilsbry & Vanatta (1905, p. 572) treated Pterodiscus as a genus; accepting Sykes's view that Ancey (1889) and Pilsbry (1893) had misidentified H. alata. they (p. 571) placed H. alata Pfeiffer in Helicamastra and (p. 572) said, although invalidly, that P. wesleyi (Sykes) was the type species of Pterodiscus. Hyatt & Pilsbry (1911, p. 120) synonymised Pterodiscus and Helicamastra, thereby bringing both alata and wesleyi into Pterodiscus Pilsbry (i.e. Tropidoptera Ancey).