CHARACTERISTIC DETAILS OF THE SPECIES Melitaea didyma and Melitaea trivia
In Melitaea didyma the disco-cellular vein is always absent from the base of the S4 (with a green border) and the marks on the submarginal area (with a red border) are usually round.
In Melitaea trivia there is always disco-cellular vein, but only in a part of the base of the S4 (with green border) and all the marks in the submarginal area (with red border) are usually triangular.