Macrostemum Kolenati, 1859

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 : 669-670

Genus Macrostemum Kolenati, 1859

Macrostemum Kolenati, 1859: 239 [Type species: not designated]; Hydropsyche hyalina Pictet (selected by Ulmer, 1957: 339).

Macronemum Burmeister, 1839: 915 [unjustified emendation of Macronema Pictet, 1836 which was a nomen nudum for Macronema ]; Ross, 1944: 114 [characterisation of M. carolina , M. transversum , M. zebratum ].

Monopseudopsis Walker, 1852: 105 [Type species: Monopseudopsis inscriptus Walker , (by monotypy); synonymised by McLachlan, 1862: 308].

Diagnosis. This genus can be distinguished from other Macronematinae genera by having medium or large discoidal cell, small median cell, and no costal crossveins and subcostal vein joining with R1. Tropical Southeast Asian species vary in wing colour pattern and these patterns are important in designating the species.

Remarks. This genus was erected by Kolenati (1859) based on the absence of apical spurs on the foretibia, but the type species was not designated. Ulmer (1907) synonymised Macrostemum with Macronema ( Pictet, 1836) and transferred all the Macrostemum species to the genus Macronema . Ulmer also recognised two species groups, based on wing venation, with one group distributed in South America and the other with a cosmopolitan distribution. Ulmer (1957) designated Hydropsyche hyalina [= Macrostemum hyalinum ] as the type species of the cosmopolitan Macronema group. Flint & Bueno-Soria (1979) divided the neotropical species of Macronema into the hyalinum group (with a cosmopolitan distribution) and the percitans group (exclusively neotropical). All the species of the hyalinum group are currently placed in Macrostemum , making the genus Macronema endemic to the neotropical region.