I tried to get a few good shots of it, and then when I got inside I posted the photo to BugGuide.net for ID. Turns out it’s a triungulin. A what now? A triungulin is the first instar of the larval form of of a blister beetle, family Meloidae. This one, the volunteer thought, was perhaps Tricrania stansburyi, the Blue Orchard Bee Blister Beetle. (He may just have been putting two and two together, though…)