The creature I saw eating the buds off my Chinese Pistachio looked like a small fly, dark like a fly but making a sound like a little buzz saw. I had no idea what it was, but when I saw there was such a thing as a sawfly I thought it an apt name for this particular insect, so have been investigating them since. Your site was the first time I have found about a sawfly in detail, except that you do not mention the buzzing sound.
Am I wrong in identifying an appropriate name instead a correct one? In which case, what the heck could it be?