From a scan of the cover of Insects Injurious to Vegetation, an 1862 book by naturalist Thaddeus William Harris. This scan has beautiful detail, and I was using it as my desktop background for a while. I think you'll enjoy it. Left-click to look, right-click to download. If you don't see your resolution, choose the next-highest. If you're not sure, try 1024x768.
