Macrostemum formosicolum (Matsumura 1931)

(Figs 9 A–9K)

Macronema formosicolum Matsumura 1931, 1132 –1133, male, Taiwan.

Macrostemum formosicolum: Malicky 1998, 771, pls. 1, 6, male, Taiwan; Malicky 2014, 1628, Taiwan.

Specimens. Holotype male (pinned, cleared abdomen was dried up in a small vial), labeled “Formosa Matsumura, Type Matsumura, Macronema formosicot”, Taiwan (HU). Ishigaki-jima: 1 male, Omoto, Nagura-gawa, 21.v.2009, K. Tojo; 1 female, Nagura-gawa, Nagura-dam-ue, 70 m a.s.l., 11.iv.2011, TI, P; 1 male, 3 females, Takeda, 8.v.2010, M. Tanaka (MT).

Distribution. Japan: Ryukyu (Ishigaki-jima). Taiwan. New to Japan.

Remarks. This species was originally described from Taiwan by Matsumura (1931), and previously known only from Taiwan (Malicky 1998, 2014). We examined the holotype male of this species deposited in Hokkaido University (Fig. 9A). The holotype has yellow forewings, and each wing has a large dark marking apically and five dark spots on the central area (Fig. 9B). Specimens examined in this study also have the same coloration although the posterior spot near the anal veins is occasionally indistinct (Fig. 9G 2). The genitalic structure of two males collected from Ishigaki-jima agrees well with that of the holotype (Figs 8 C–F, H–K) although the phallotremal sclerites of the holotype are protruded from the apex of phallotheca, probably because of drying.

In addition, one Macrostemum female was collected from Iriomote-jima (Aira-gawa, 5 m a.s.l., 25.iii.1999, by TI & AO). Forewings of this female bear similar markings to those of M. formosicolum, but lack a dark spot on the anal area. Although this female probably belongs to this species, we hold the identification until more specimens become available.

Japanese name. Taiwan-shima-tobikera.