I know you can't identify without a photo and I don't know if this was what bit me.  But a small 3mm round black insect crawled across the back of my hand. It looked like a black small ball shape. I just took piriton but on day 5 I needed Penicillin, antibiotics, brufen and anti-histamine drugs due to an infection travelling up my arm.  The A&E considered admitting me to have an IV overnight.  For someone who is not prone to allergic reactions or insect bites being more effective than an inconvenient lump, this was quite a surprise.  I'm not able to google this one because I couldn't scroll through images of insects.  This a first for me! regards

Hi Suzanne,

it sounds like you had a nasty experience! It would be useful to know where you are based, in order to identify the likely culprit. That said, I cannot think of any regular biting insect that matches the description you provided.

My initial thought was ticks, but interestingly I have found other anecdotal references to people suffering from bad bites from 2-3mm shiny black beetles in the UK. Usually these have happened outdoors, near fields of crops.

I will investigate further!

The best option I have heard of so far was suggested by a colleague of mine with much better entomology skills than me (thanks Beulah). She has suggested that the biting insects are actually nymphs of mirid bugs. Rather than bite they stab with a tube to drink blood.

However, for a confident identification it is always best to have a specimen, or at least a photo to work from. If you happen to see one of these insects again please try to catch it in a matchbox or similar, then put it in the freezer for a few days to kill it. Then you can pad the box with cotton wool, tape it up and send it to a museum - feel free to send it to me at the Horniman museum (address can be found at http://www.horniman.ac.uk). If you can get a photo, but not the insect, just email a copy to askabiologist@googlemail.com

Sorry I can't help more - perhaps someone else has some ideas?