Following on from my extreme closeups of a large Bumblebee a couple of days ago, we'll tackle a large Hoverfly. This one was about 20mm long, so comparable to a bee and clearly mimicking one. There are a few ways to tell that it's definitely a Hoverfly, but they are fairly subtle and I'll leave this fantastic page to do the hard work. Really it's a fascinating read that gives an insight into a whole unexpected world of interesting details. Suffice to say that you may have to examine the vein pattern on the wings to be sure that what you're looking at really is a Hoverfly.
Below we can see her head on. We can tell it's a she because of the fairly wide gap between the eyes, which would nearly touch at the top in a male.
Finally a profile shot. I've committed the cardinal photographic sin of not having the eyes in focus here, but actually I picked this shot for good reason as it shows the fairly flattened abdomen that in my mind says 'hoverfly' instantly when I see them. Maybe it's just me, and maybe I'm plain wrong, but this is I think the main visual cue that I use. That and the fact that they're behaving like Hoverflies of course.