Unknown flies

Unknown flies

Observation - Unknown flies. Description: I have very many small black flies in my garden today. Pics of 3 separate individuals attached. They were resting in very close proximity and I've assumed they are all the same species. I've seen many recent posts for St Mark's fly, but I can't see the

I have very many small black flies in my garden today. Pics of 3 separate individuals attached. They were resting in very close proximity and I've assumed they are all the same species. I've seen many recent posts for St Mark's fly, but I can't see the diagnostic(? spine on the front tibia.