We get tiny little red spiders in very hot dry weather like we are having now. The year before last when we had similar conditions, they were all over the lime trees in my street and were making great inroads into our houses (victorian terraced) - cheeky blighters. I contacted the local council who told me that they WERE red spider mites which would be washed away with the next rain. This year, I keep finding them in the kitchen - not on any plants - and they are bigger than before !! I'm going to wipe everything down with a damp cloth and see what happens.