I believe this is a book louse. Sorry about the quality; that's the best macro that I coaxed out of my Canon PowerShot (don't have an actual macro lens yet). This one was walking along my marble window ledge, where a few dead midges have collected. Perhaps the louse was scavenging on these. I somehow spotted the insect without a hand lens and without bringing my head close to the ledge ... don't quite know how I managed to do that.