I checked off male because males of both flavifrons and sitkensis are the only ones in those species to have black on the front of T3 and T4 (Williams et al., Bumble Bees of North America, Princeton University Press, 96, 99). I have moved this to flavifrons because the bee lacks brownish yellow at the rear of the abdomen (as in sitkensis), and has yellow on the side of T5 (Ibid.)