Macrostemum formosicolum ( Matsumura 1931 )

Ito, Tomiko & Nozaki, Takao, 2018, The family Hydropsychidae Curtis (Trichoptera) in the Ryukyu Archipelago, southwestern Japan, Zootaxa 4504 (4), pp. 545-565 : 560-561

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.

Figures

FIGURE 2. Diplectrona burha Schmid and D. albofaciata Ulmer. Diplectrona burha (2A–2I): male (2A–2F): 2A, abdominal segments V–X, left lateral; 2B, genitalia, left lateral; 2C, same, dorsal; 2D, left inferior appendage, ventral; 2E, phallic apparatus, left lateral; 2F, apex of phallic apparatus, ventral; female (2G–2I): 2G, abdominal segment VIII, left lateral; 2H, abdominal segments IX–X, left lateral; 2I, abdominal segments VIII–X, ventral. Diplectrona albofaciata (2J–2R): male (2J– 2O): 2J, abdominal segments IV–X, left lateral; 2K, genitalia, left lateral; 2L, same, dorsal; 2M, left inferior appendage, ventral; 2N, phallic apparatus, left lateral; 2O, apex of phallic apparatus, ventral; female (2P–2R): 2P, abdominal segment VIII, left lateral; 2Q, abdominal segments IX–X, left lateral; 2R, abdominal segments VIII–X, ventral. Abbreviations: V–X = abdominal segments V–X; l.l. = lateral lobe (paired); m.c.l. = mesocaudal lobe (paired); p.a. = preanal appendage (paired). Arrows, see text.

FIGURE 8. Hydropsyche verrucosa (Ulmer). Male (8A–8F): 8A, genitalia, left lateral; 8B, same, dorsal; 8C, left inferior appendage, ventral; 8D, phallic apparatus, left lateral; 8E, apical part of phallic apparatus, dorsal; 8F, same, ventral. Female (8G, 8H): 8G, genitalia, left lateral; 8H, same, ventral. Abbreviations: VIII–X = abdominal segments VIII–X; rec. = receptacle of inferior appendage (paired).

FIGURE 9. Macrostemum formosicolum (Matsumura) and M. okinawanum (Matsumura). Macrostemum formosicolum (9A– 9K): Holotype male from Taiwan (9A–9F): 9A, habitus, dorsal; 9B, left forewing, dorsal, venation and dark markings; 9C, genitalia, left lateral; 9D, same, dorsal; 9E, right inferior appendage, ventral; 9F, phallic apparatus, left lateral; specimens from Ishigaki-jima (9G–9K): 9G1, 9G2, right forewings, venation and dark markings (9G1, female; 9G2, male); 9H, male genitalia, left lateral; 9I, same, dorsal; 9J, phallic apparatus, left lateral; 9K, same, ventral. Macrostemum okinawanum (9L–9Y): Holotype male from Okinawa-jima (9L–9O): 9L, habitus, dorsal; 9M, right forewing, dorsal; 9N, genitalia, dorsal; 9O, right inferior appendage, ventral; specimens from Okinawa-jima (9P–9T): 9P1, 9P2, male right forewings, venation and dark markings; 9Q, male genitalia, left lateral; 9R1, 9R2, male genitalia, dorsal; 9S, phallic apparatus, left lateral; 9T, same, ventral; specimens from Amami-o-shima (9U–9Y): 9U1,9U2, male right wings, dorsal; 9V, male genitalia, lateral; 9W, same, dorsal; 9X, phallic apparatus, lateral; 9Y, same, ventral.