Mayfly types and additional material (Insecta: Ephemeroptera) examined by F. - J. Pictet and A. - E. Pictet, housed in the Museums of Natural History of Geneva and Vienna Author Sartori, Michel Musée cantonal de zoologie, Palais de Rumine, Place Riponne 6, CH- 1005 Lausanne, Suisse. & Département d’Ecologie et d’Evolution, Biophore, Université de Lausanne, CH- 1015 Lausanne, Suisse. Author Bauernfeind, Ernst Naturhistorisches Museum Wien, Burgring 7, A- 1010 Wien, Österreich. E-mail: ernst. bauernfeind @ nhm-wien. ac. at * Corresponding author: michel. sartori @ vd. ch ernst.bauernfeind@nhm-wien.ac.at text Revue suisse de Zoologie 2020 127 2 315 339 journal article 119274 10.35929/RSZ.0022 8839740a-00d8-44ff-b6cf-5cee99c19643 0035-418 5743794 Caenis argentata F.-J. Pictet, 1843 Caenis argentata F.-J. Pictet, 1843 -1845: 279-280 , pl. 43, fig. 6. – Kluge, 2020 ( nomen dubium ). Caenis halterata ( Fabricius, 1777 ) . – Ulmer, 1921: 248 (synonymization). Accepted name: Caenis argentata F.-J. Pictet, 1843 nom.dub . Locus typicus: “… se trouve en Sicile ”. Type material: NMW ; holotype [by monotypy], female subimago . Remarks: F.-J. Pictet wrote “Je ne connais que la femelle subimago de cette espèce… elle m’a été communiquée par le musée de Vienne ”. It is, however, rather doubtful whether the specimen in the NMW actually represents the type specimen: female subimago / Caenis argentata ? Kollar lactea Hffm. [Kollar’s handwriting] / Caenis horaria (L.) det. Malzacher 1983 [no collector’s label, no locality]. Ulmer (1921: 248) erroneously quoted three male subimagines in the NMW carrying F.-J. Pictet’s label: “... davon stammen zwei aus Sizilien , eins aus Ischl.”. None of these specimens actually bears F.-J. Pictet’s label nor could they have represented type material, and most probably Ulmer’s remark was based on a confusion with later acquisitions from Sicily not seen by F.-J. Pictet. Two additional male specimens and one female (in the NHW, all without labels) have been transferred to glycerin: “ Caenis horaria (L.) sub nom. C. lactea (Pict.) det. Malzacher 6. 1983”. None of them can be considered to represent type material. Caenis horaria has so far not been recorded from Sicily and in our opinion it is most likely that Kollar incorrectly labelled a specimen of unknown origin at a later time. The specimen in question lacks the “Pictet vidit” label as well as any evidence concerning its origin, and it therefore seems justified to consider the name Caenis argentata F.-J. Pictet, 1843 as a nomen dubium .