Found at midnight on tree trunk behind house, and brought inside to photograph. A PDF doc says all Lampyridae larvae are luminescent so I assume they all have a light-producing organ. The second-last abdominal segment on this individual has paler edges than the rest, but the last three segments are not completely white, as they are in luminescent adults.
Two recent photos by Tom Murray (1, 2) show more white/contrast than this one, so maybe those really are fireflies (?) - and this one is a net-winged beetle (?)
Hoping someone can shed more light on the subject. (pun? what pun?)