Can you please id these fast-moving bees, if they are bees, for me? I am quite used to other solitarys but these have arrived today and are in the same area of my garage wall as they were last year at this time. Last year they were accompanied, if that is the word, by small, grey, red-eyed flies which appeared to be parasites. As I have said, these bees are very fast-moving and difficult to photograph, as they only settle for a few seconds. They are interested in the holes in the mortar in this small area of the wall. Also, the hot sun appears to attract them.
Thanks, once again
I am no bee expert, but the bees you describe look to me like sandbees, genus Andrena, see:
Sandbees, as their name implies, usually built their nests in sun-exposed sandy areas, which would partly fit what you describe.
As for the fly, I think this could be a member of the family Tachinidae. Some of them are parasites of bees. There is a UK database for them, check out here:
If you feel so inclined you could browse through the 275 species listed there and see if you can find a match for your animal.
Hope that helps