Went back and collected 3 pupae.....they all eclosed this morning

You might be right, , both species might be on the same hostplant at the same time...... out of 3 eclosed, one is smaller and having a straight termen, the other two with convex termen.

Can it be 2 coincidences of both species on the same plant and eclosing at the same time???

May be we should consider investigating the genitalia of the smaller individual with straight termen to verify if it is a E. thrax or a E. torus????