Last summer, when the house was very quiet, I could hear a high pitched noise in the living room. OH couldn't hear it all; he's partially deaf and the noise was too high a frequency for him to pick up anyway. It went on for days and I couldn't track it down at all. This went on for more than a week and then, late one evening, whilst sat reading, a large yellowy/orange insect flew right past my head and latched on to the back of the living room door. It was well over 2 inches long and it clung there, flexing its wings and pulsating. It knocked me sick! I vacuumed it up, at arms length and forgot about it. The next day, 3 more flew around the room and clung to the walls, window shutters and door. I ran to grab the Dyson again and that when I saw that insect no. 1 was still alive, flying round and round inside the dust box and it and almost doubled in size. His mates quickly followed him up the long tube to oblivion! It was then that I realised that all of them had flown from the same spit in the room; the log pile at the side of the wood burner. Unknown to me, one of the logs (the one at the very bottom of the pile, naturally) had got an infestation of Wood Wasps and the noise I'd heard had been them grinding their way out of the log, ready to hatch. They were truly monstrous! The whole delivery of logs were dumped because I had no way of knowing if any more logs were infected with them. And just having one in your house can cause immense damage to wooden furniture, joists, beams and floor boards.
Never want to see another Wood Wasp as long as I live!