Black-veined White Aporia crataegi
This butterfly, once common in southern England, became extinct in the British Isles around the 1920s probably through loss of habitat rather than collecting. In my youth therefore, I was determined to find a last remaining insect and spent many a day chasing whites to find that the black veins I thought I had seen were just well marked ones on a Green-veined White.
This was the first time I had seen it outside a museum and I hadn't realised that it is quite a large butterfly and that the black veins are obvious from quite a few metres away. Aporia crataegi has no other markings and could possibly be confused with the Clouded Apollo which also flies in this area.
Several species of butterfly were attracted to both the Cardamine raphanifolia (Radish-leaved Bittercress or Greater Cuckoo flower) and to the Echium vulgare (Viper's-bugloss).