Rediscovery of the mysterious Taiwanese micromoth Pachyrhabda citrinacma Meyrick, 1936 (Stathmopodidae) in museum and field, with notes on the fern-spore feeding larva

Pachyrhabda citrinacma Meyrick, 1936, an endemic species to Formosa (Taiwan), was named by Edward Meyrick based on two specimens collected by Syuti Issiki. Despite some newly discovered stathmopodids exhibiting characteristics matching the original description, the lack of information regarding the type specimen depository led to the species remaining elusive since its initial naming. In this study, we successfully rediscovered a P. citrinacma specimen at the Insect Museum of National Taiwan University, where Syuti Issiki used to conduct research. The present article provides comprehensive morphological details for both sexes, as well as unveiling the genitalia characters and life history of this species for the first time. Larvae feed on spores of a range of fern species belonging to a few different families.