Large individual. 58cm long at tail fork.
Male, 12 mm. B. vagans / sandersoni.
Unsure what the best identifying characteristic for males is. Antennae (length A3 vs A5; A3 width vs length) or gonostylus (thickness of inner margin)?
Is the last photo (pic 6/7) the right area to focus on? Is that the submarginal groove below the "upper" margin? Pictures in Williams et al. are very small.