Hysterosphaerius Melichar 1906

Genus Hysterosphaerius Melichar, 1906 Hysterosphaerius Melichar, 1906: 98. Type species: Hysterosphaerius sexpunctatus Melichar, 1906, by original designation and monotypy. Diagnosis. Metope elongate, enlarged below eyes, without carinae, but with two lateral rows of traces of larval sensory pits (pustules). Coryphe transverse, twice as wide as long medially, concave. Postclypeus curved almost at right angle in lateral view, with strong median carina. Fore wings slightly concave or flat on clavus, with large semicircular projections of the costal margins basally under eyes in lateral view, with relief reticulate venation and cells with dense punctation. Fore wings not narrowing apically – nearly truncate from the apex of clavus, without hypocostal plate, claval suture indistinct. Hind wings nearly as long as fore wings, with deeply concave costal margin and reduced anal lobe. Hind tibia with two lateral spines distally and with five apical spines. First metatarsomere with two latero-apical and five intermediate spines in whole straight row. Male anal tube large, enlarged and deeply concave apically in dorsal view. Penis symmetrical; each dorso-lateral lobe of phallobase with triangular-shaped basally, but strongly narrowing apically and curved at right angle apical process. Capitulum of style on long neck. Composition and distribution. Monotypical genus known from Singapore Island.