Battlefield Butterflies

In the new issue of Butterfly magazine, there's an excellent piece by Peter Marren on the Rolling Stones' Hyde Park concert in 1969, at which hundreds of Large White butterflies were released in memory of Brian Jones, who had died just days before. I've written about the occasion here before, and quoted Charlie Watts' remark about the high casualty rate among the unfortunate Large Whites, that 'It was like the Somme.'
 I took this for rock-star hyperbole, and perhaps that's all it was – but, as Marren points out, it was also a surprisingly apposite image, for the  battlefields of the Western Front often witnessed similar summer snowstorms of white butterflies. The war artist William Orpen describes one at the Somme in August 1917:
'The dreary, dismal mud was baked white – and pure dazzling white. Red poppies and a blue flower [most likely cornflower], great masses of them, stretched for miles and miles. The sky was dark blue, and the whole air up to a height of 40 feet thick with white butterflies. Your clothes were covered with butterflies, it was like an enchanted land...'
 Marren quotes another visitor who wrote of the great profusion of butterflies that 'it was as if the souls of the dead soldiers had come back to haunt the spot where so many fell. It was eerie to see them. And the silence! It was so still that I could almost hear the beat of the butterflies' wings.'
 In one of the most famous novels of the First World War, Erich Maria Remarque's All Quiet on the Western Front, the narrator, Paul, who collected butterflies in his boyhood, notices their presence amid the devastation of the battlefield: 'The grasses sway their tall spears; the white butterflies flutter around and float on the warm wind of the late summer.' Later in the novel, he sees 'brimstone-butterflies, with red spots on their yellow wings. What can they be looking for here? There is not a plant or a flower for miles. They settle on the teeth of a skull.' A grisly image of the endurance of nature and beauty amid all the man-made horror.
 The film version of All Quiet on the Western Front ends, famously, with Paul reaching out towards a butterfly and being casually shot by a French sniper. It's a devastating scene – and, for the watching aurelian, it begs the question, What is that butterfly? It sure ain't a Large White, nor even a Brimstone. Consulting my Higgins and Riley field guide, I can't identify it as any European species. I imagine the production people decided to go for something big and showy to justify Paul's fascination (and perhaps to show up well on screen), but I can't help feeling that a Large White would have been far more eloquent...
 This link should bring up the famous finale. If anyone can identify that butterfly, do let me know.