Fritillary - Silver Washed

Fritillary - Silver Washed

Observation - Fritillary - Silver Washed - UK and Ireland. Description: Large fritillary - dark veins on the forewing and markings on the hind wing look like SW - how can I be certain?

Large fritillary - dark veins on the forewing and markings on the hind wing look like SW - how can I be certain?