Macrostemum indistinctum Banks, 1911

Uy, Christine Jewel C., Malicky, Hans & Bae, Yeon Jae, 2018, Review of the filter-feeding caddisfly subfamily Macronematinae (Trichoptera: Hydropsychidae) in tropical Southeast Asia, Raffles Bulletin of Zoology 66, pp. 664-703 : 679-681

Macrostemum indistinctum Banks, 1911

( Figs. 119–122 )

Macrostemum indistinctum Banks, 1911: 106 [Holotype male; India; MCZ]; Malicky, 1998b: 777 (redescription).

Macronema brisi Navás, 1930: 5 [Holotype male; China; synonymised by Malicky, 1998b: 777].

Macrostemum saowapa Chantaramongkol & Malicky, 1986: 528 [Holotype male; Sri Lanka; HMPC; synonymised by Flint, 2003: 819].

Diagnosis. Male. Antennae 25 mm in length. Antennal flagellum dark brown with darker striations. Forewing 13 mm and hind wing 7 mm in length. Mesoscutum and mesoscutellum without evident markings. Tibial spurs 2.4.4.

Male genitalia. Inferior appendages two-segmented, harpago long and slender ( Fig. 120 ). In lateral view, phallus with pointed structure, posterior of apex pointing apically but very minute not like other species ( Fig. 122 ). In dorsal view, segment X divided medially with inner portion consisting of evident folds running diagonally ( Fig. 121 ).

Female. Antennae broken. Antennal flagellum same as males. Forewing 11 mm and hind wing 8 mm in length. Mesoscutum and mesoscutellum without evident markings. Tibial spurs 2.4.4.

Material examined. Indonesia: 1 male, 1 female, Sumatra, Prapat, coll. H. Malicky, 17 April 1997 ( UPLBMNH) ; Vietnam: 5 males, 2 females, Dak Lak Province, Yok Don, coll. D.H. Hoang, 26 March 2001 (KU).

Distribution. India, Sri Lanka, Cambodia, Laos, Malaysia (Perak), Sumatra, Thailand, Vietnam.

Remarks. The deposition of the type specimen of Macrostemum brisi Navás, 1930 was not indicated (see Remarks under Macrostemum centrotum Navás , above). The original description of Banks (1911) includes only the illustration of forewing lacking description and illustration of male genitalia. Malicky (1998b) redescribed the species. The eyes of males are larger than those of females, whereas wing pattern is consistent ( Fig. 119 ).

Figures

Figs. 112–125. Macrostemum hestia. 112, right forewing; Male genitalia: 113, 115, lateral; 114, 116, segment X dorsal; 117, phallus lateral; 118, phallus tip. Macrostemum indistinctum. 119, right forewing; Male genitalia: 120, lateral; 121, segment X dorsal; 122. phallus lateral. Macrostemum luteipes. Male genitalia: 123, lateral; 124, segment X dorsal; 125, phallus lateral. Scale: 112, 119 = 2 mm; 113–118, 120–125 = 0.02 mm (123–125 redrawn from Kimmins, 1955).