Abstract

Rutaraphes Jałoszyński was proposed for an unusual species discovered on Shikoku, Japan. Rutaraphes shikokuensis Jałoszyński has a unique aedeagus, with an asymmetrical median lobe, lacking parameres, and the diaphragm to which the internal muscles are attached is situated not sub-medially, sub-basally, or basally, as in most genera of Stenichnini, but sub-apically, and nearly transverse in relation to the long axis of the aedeagus. It is here confirmed that this highly unusual structure was not a teratology in the sole known specimen, because the newly described Rutaraphes taiwanicus sp. n. shares similar genital structures. The new species occurs on northern Taiwan, and differs from R. shikokuensis in (among others) male modifications of the head. The new discovery extends the known range of Rutaraphes over 1500 km SW, suggesting that also the islands of the Ryukyus may be inhabited by this rare genus.