I came across a small webworm nest yesterday in an American sweetgum (Liquidambar styraciflua) in a park that I frequent in Hamilton County, OH. It strongly resembled an early instar Fall Webworm (Hyphantria cunea) nest. I've even taken pictures in the past of fall webworms on this same sweetgum tree. However, fall webworms are just about finished for the season. I've been finding late instar caterpillars that have abandoned their nests and are crawling around looking for a place to pupate for the winter.
I tore the nest open to find it did contain caterpillars, but none that I have ever seen before. A web search revealed a reference to Sweetgum Webworm (Salebria afflictella, family Pyralidae) on page 485 of the book, Pirone's Tree Maintenance, 7th Edition, by John R. Hartman, Thomas P. Perone, and Mary Ann Sall (Oxford University Press, 2000). However, almost every other search result only referenced fall webworm on sweetgum.
Further web browsing revealed that both the scientific and common names have changed since the 2000 publication. The common name is now "Sweetgum Leafroller" and the scientific name is Sciota uvinella. The leaves did appear to be slightly rolled within the nest; however, the overall structure may also be described as a webworm nest. The sweetgum leafroller / webworm caterpillars appear to remain within their nest to feed as leaf skeletonizers.
I could find no references for the life cycle of the moths, nor could I find any information on how commonly the caterpillars occur on their namesake host. I'm not sure if this means they are uncommon, or if they have been flying below the radar by being mistaken for fall webworm. Indeed, had I not torn the nest open, I would have walked by the nest assuming it was fall webworm. I now wonder how many times I've made this error in the past.