I was thinking about photographing a vetch when I noticed a small white object. When I looked more closely I saw it was the head of an insect so I took the photo.
It seemed lifeless. It would appear to be a drone fly Eristalis tenax except for the white face. I wondered if it had been parasitised or maybe the white was the result of fungus. Anyone care to speculate?
Doesn't Eristalis normally have a white face?
I don't hink so. The image you provided a link to has a lot of reflected light off the face but I don't think it is as white as the specimen in my photo above. Here's a drone fly I photographes last month
Yes, there's a thin white line around the structure that supports the antennae but it is nothing compared to that in the first photo.
Nothing happened to that fly. It's a normal drone fly Ersitalis sp., probably E. tenax. You just happened to photograph its face. Google for Eristalis pictures and you will get some like this one. Your second photo was taken from above the insect, so you can't see its face.