Posted by John Carr on 11-08-2023 19:40
#3
In Grichanov's key,
D. diadema has "Facial clypeus at apex convex, not adjacent to eyes and distinctly projecting below level of lower eye-margin" while
D. griseipennis has "Facial clypeus at apex straight, adjacent to eyes and not projecting below level of lower eye-margin".