Hoverflies

From late last month: what I first thought was a bee, but then I noticed the dipteran-like antennae.  A male hoverfly, probably Merodon equestris (Diptera: Syrphidae), a species which seems to show quite a lot of variation in the colour of its thorax, from yellow, through brown, to yellow and black, and all black.  A couple of weeks later I came across the following one:

Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2010-05-31 and 2010-06-15, respectively.