1A. Telson of male elongate, at least twice as long as uropod 3; telson of female distinctly tapered and twice as long as wide …………. 2

1B. Telson of male not elongate, either shorter or just slightly longer than uropod 3; telson of female not distinctly tapered, usually not twice as long as wide (except B. brachycaudus) …………………………………… 3