My husband and I went hiking at Ijams Nature Center in Knoxville on Sunday. A large Smilax (greenbriar) vine was hanging from a tree near the trail. I noticed it was infested with large gray aphids; one section of the aphids was clear, however. When I looked more closely, I saw a 1" caterpillar that was eating the aphids! I posted it on Bugguide and learned it was a Harvester butterfly caterpillar. Here is the link to a photo of it that I posted on my blog: http://blog.easttennesseewildflowers.com/ I have seen other aphids on my milkweed leaves being eaten by syrphid fly larvae, but I was surprised to learn that some caterpillars also eat them. That is what I love about nature, there is always something exciting and new to learn! :) Kris Light Oak Ridge