I had a serious allergic reaction when stung by these wasps and am trying to identify them. The wasps seem clearly to be yellow-jackets (Vespula sp.), but I'm confused about the aerial nest. My internet search tells me that yellow-jackets nest only undergound (or in similar locations above ground - on a rotten stump or enclosed in house walls, abandoned cars, etc.). These wasps are from a heart-shaped aerial nest, about 8 inches tall, fixed directly to the trunk of an American beech (roughly 4 inches in diameter), about 15 feet off the ground, one exit hole. The wasps aren't clearly visible, but they were black and yellow, with a yellow line on the lateral margin of the eye, about 1/2 inch in length. Can someone confirm that Vespula species nest in this way?