There is a type of mite that infests the trees and they will drop lady bugs because they eat them, the mites can kill the forest. Our Girl Scout camp had an adopt a ladybug fundraiser for this purpose. The only way to get rid of the asian ones is to have your house sprayed, once they get in it will just keep getting worse. The red lady bug has symetrical spots on each side and are very beneficial for your garden because they eat aphids among other things.