---

It's defenitely Riponnensia (no O. nobilis, for the eyes are meeting over a very short distance in nobilis).
Because I cannot reliably estimate the length of the 3rd antennae, we will stick to R. splendens/longicornis.
[Between these two, I would guess longicornis though]
Would be nice to collect some next year and send them to me please. :p

Can you describe me the exact environment where you found them?