Cybister tripunctatus
imago
Cybister tripunctatus
We Japanese call them
kokgatano
. They length 24-29mm and are hardly in Mainland but much only in Southwest-Islands of Japan. Ofcourse I haven't even seen wild. they look like lewisianus, but it will be easy to distinguish if you got used to see.
larva
Cybister tripunctatus
pupa
Cybister tripunctatus