Female species.
It is quite a challenge to tell the O. brunneum and the O. coerulescens apart from each other.
One of many characteristics are on the forewings. The O. brunneum have several cells which has been doubled - here 4 or 5, the O. coerulescens have just one row, mayby 1 cell is doubled.
As seen in this picture, they are often found sitting on the ground.