The fluttering turned out to be a brown skipper, flailing around with its proboscis apparently held in the tenacious grip of a small ambush bug.
By the time I returned with camera equipment, the skipper had stopped moving and the ambush bug had reeled it in to feed.



--Rik
Canon T1i with Canon 580 EX II flash and small softbox, ETTL mode at f/11 and 1/200 second, ISO 100.