Fig. 2

Scheme of measurement for sclerotized structures of Quadriacanthus spp. a Ventral anchor. b Dorsal anchor (a, total length; b, point length; c, total length of accessory sclerite; x/y, curvature of shaft). c Ventral bar (d, component length). d Dorsal bar (e, total length; f, total width excluding the process; g, thickness at mid-region; h, process length). e Hook (i, total length). f Vagina (j, total length). g MCO (k, total length; l, trace length of copulatory tube)