When I talked to an owner of the native nursery I visited last weekend, I told him about the Crimson Patch caterpillars and he said he hadn't seen them in 3 or 4 years. He happened to mention that they can also use ruellias as host plant, which I hadn't ever heard about. So today I found one caterpillar eating on my Ragin' Cajun Ruellia...pic below! All the others were on Flame Acanthus. They're mostly pupated now...I took a pic of one of the chrysallis, kind of speckled.
