Horseflies.

Horseflies and I have an arrangement, they love to bite me, and I hate the little b******s!
There's something in my blood they just love, they will come for miles to bite me. I have been in a field with 3 mates and the horseflies have totally ignored them and I'm covered in the bloody things, my mates are laughing while I'm leaping around screaming "GER OFF!!!!" and flapping my arms like the first man attempting flight. Although it makes no difference they still bite me.
To add insult to injury I'm mildly allergic to the bites, nothing serious I just get a big painfull lump, lovely!!
At this point there should be a pic of a horsefly, but it's hard to photograph and scream while running away so you'll have to look them on Google.