Can anyone help me identify a flying insect that has made its home in a log seat next to my greenhouse. it is black with 3 body sections, about 1.5 cm long and i can't see any stinging or biting equipment on it. it does not seem agressive. there are several of them silently going in and out of holes that they have made in a log. there is plenty of sawdust so i imagine that they have made quite an extensive nest inside the log. The log is not swarming. there only seems to be one or two around at any one time and they go in for a few seconds then come back out again.
I was wondering if they were good or bad. can anyone help identify.
