Genus Systenus Loew

Systenus Loew, 1857: 34 .

Type species, Rhaphium adpropinquans Loew, 1857 (= Rhaphium pallipes Roser, 1840), des. Foote et al. 1965: 517.

Diagnosis. The genus is easily recognized by the males with postpedicel triangular or subrectangular at base, elongate about 2–4 times longer than basal width, slightly to strongly tapered at apical 1/2 to 2/3 (Figs 1B, 2B, 3B, 4B); proepisternum with 1 pale seta (Figs 3B, 4B); R 4+5 and M 1 subapically bowed, M 1 beyond dm-m crossvein with flexion (Fig. 1D); six strong dorsocentral setae (Fig. 1C); abdominal segment 7 with tergite and sternite distinctly elongate, forming a peduncle (Figs 2C, 3C, 4C); only one single lobe of the surstylus is present (Figs 1F, 2F, 3F, 4F). See Bickel (1986, 2015) for a complete diagnosis.