You can sprinkle diatomaceous earth all over your mondo grass. It won't hurt the grass. Good luck!
Here, try this:
Naomie makes some good points on prevention.
These critters are naturally drawn to our house, a slab foundation and walk in under the front door. I put down sticky pads and am amazed by what crosses over the floors when we think the house is free if insects. At times, these sticky pads have been the only solution to a very annoying middle of the night chorus of these pests.
However, I will try the DE as mentioned by Courtney when the season comes.
Sprinkle the grass with a bit of Sevin Dust or other insecticide.