This is a green bug for St. Patrick’s day. (I’m reaching; I know. Happy Birthday, Eric!)
I’ve talked a bit about gall-forming insects in the past, but I think it bears repeating how extremely cool this adaptation is. Galls are created by parasites (fungi, bacteria, mites, wasps, aphids, flies, midges, psyllids, etc.) that use chemicals to co-opt the physiology of their host and cause the plant to grow abnormal structures that make a comfy little home for the parasite in question. Opening up these particular leaf galls revealed tiny wasp pupae, developing in the safety and luxury of their own private green room. Chemical warfare at it’s most refined.
P.S. Does anyone know if any wasps outside Cynipidae form galls? That’s the only family I’m familiar with.