Hey check this out. I love it when this happens. Last year I had butterflies and ladybirds in the house, this year an amazing hoverfly. Pretty sure its a hoverfly. There are many different types of hoverfly and they all eat pests. Provide lots of open flowers, especially Umbelliferae like fennel to attract them. This one seems to like jazz. It just appeared by my computer wandering over a cd box. Extra marks if you can tell me who the jazz hands belong to.