Among the species heretofore referred to the genus Erax is a small group in which the first submarginal cell is divided by an oblique cross vein into two cells. The venation is similar to that of the genus promachus, except that the foremost of the two apical submarginal cells is shorter, and teh third vein curves forward to the costa before the apex of the wing, instead of curving backward to the hind margin beyond the apex.