How do you know they are there if ya cant seeum?
*Gina Slinks off to her room, slowly...*
Umm, you can feel them bite... I can attest, after spending a couple of days in Pennekamp SP CG in the Keys one year that after one picks up a bunch of them in an egg they will live on for about three days. If I were to go into No-See-Um country for a while, I would take the NSM netting that I salvaged from an old tent and put it over my window screens (it has finer mesh, but also blocks the flow of air more than the standard skeeter-skreen).
BTW, DEET doesn't work so well for NSMs; one needs something thick like SkinSoSoft or vegetable oil on the skin to mess them up.