It behaved like a bee, hovering and apparently sucking nectar from heather flowers. It didn't have any obvious nectar pouches on its legs. I'd love to know what it is, we've holidayed in this area of Scotland for over ten years and never come across these before. Thanks.
Thanks, I thought they were beautiful flies and I like to know what I'm looking at. With regard to your comment about the caterpillars, something else we had been trying to identify since our holiday were large orange banded caterpillars; looking up this fly family gave us an answer to that too as they were Fox moth caterpillars which the flies use as hostsfor their larvae. I was using 'Bugs Britannica' to try and identify the fly but I can't find any mention of this family of flies at all there - is there a reason for that?
I don't know much about Bugs Britannica but there are about 20,000 species of insects in the UK and so any book can only cover a selection. And when having to choose what to miss out the Tachnidae would likely come near the top of that list - they're mostly unattractive and they have rather gruesome lifestyles - they're all parasites, I think.
For IDing flies diptera.info might be a good place to look -