🚀 go-pugleaf

I pruned our plum tree last weekend and cut off a dead branch about 8 cm
in diameter. I cut it into log sized chunks and set them down. Later my
wife (whom I directed to clean up :-) noticed that if you dropped one of
the logs, an intense buzzing sound occured for a few seconds. I immediately
stated authoritatively that it must be termites.

However after several of the dropping experiments, a black bee-like
creature emerged and flew around.  It was almost 2 cm long (I would
estimate) and was almost shapeless (like a large furry raisin).  Later a
yellow version came out of the log, and flew in ever higher circles till
it vanished.  The yellow one was thinner and had a definite waist.  We saw
about four black ones altogether, they mostly stayed on the ground and
seemed torpid as if they had been hibernating.

The log had a hole through it about 1 cm across. Would someone please tell
me what these animals are?

Dick Jackson