Published online by Cambridge University Press: 31 May 2012
1. Aradus concinnus, Bergr.— Female: Fifth ventral segment as long in the middle as at the sides, with a transverse obtuse-angulated keel a little in front of the almost straight middle part of the apical margin, this keel at the ends coalescing with the apical margin, apial angles of the segment reaching a little beyond the slightly rounded apical margin of the middle part of the sixth ventral segment, which is broader than long, apical angles of this segment nearly reaching apex of second genital segment, which does not project behind apex of abdomen and is half as long as the transverse first genital segment, this more than twice as broad at base as at apex, apical gential segment, this more than twice as broad at base as at apex, apical genital lobes shortly prominent beyond apex of abdomen, somewhat distant interiorly, inner margin rounded, apical margin oblique, notched before the middle, dorsal gential segment broadly rounded at apex.