Key to adult male Megaloprepus

1 Hind lobe of prothorax with recessed middle area............................................................ 2

1´Hind lobe of prothorax straight.......................................................................... 3

2 Hind lobe of prothorax with a small recessed area in the middle; paraprocts in lateral view pear-like with A and B smoothly convex, D = 51.7% of L-L’ length.............................................................. M. latipennis

2’ Hind lobe of prothorax with a large recessed area in the middle, forming two rounded lateral lobes; paraprocts in lateral view quadrangular with A angulated convex and B slightly concave (almost straight), D = 69% of L-L’ length; blue wing band narrow; pseudostigma nearly quadrate............................................................ M. brevistigma

3 Paraprocts in lateral view roughly triangular with A and B slightly convex and sub-equal, D = 66% of L – L’ length; wings broad with additional milky-white band proximal of the metallic blue band.................................. M. caerulatus

3’ Paraprocts in lateral view roughly triangular with A convex and B straight, D = 76% of L – L’ length............ M. diaboli