Green or grey?

We did a favourite walk at the weekend between Pateley Bridge and Wath, wandering through wildflowers and blazing bushes of gorse. Up by the river Nidd, back by the old quarries on the skyline, with the Sportsman's Arms at Wath a very fine halfway house. I am also fond of this hamlet for the odd reason that I broke my arm there aged nine when my older sister got off the bottom of the see-saw while I was at the top. We had to drive all the way to Leeds with a green-stick fracture which bent my left arm into the shape of a Z-bend sign. I think it taught me that things aren't always as bad as they look...

En route this time, we saw lots of Green-veined Whites like the one above. Close examination of them intrigues me about the subtlety of butterfly scales. From one angle or in one light, the delicate veins appear the colour of greenish mould, as above; from another, eg below, they are incontrovertably grey. There is also a Black-veined White, or was. It became extinct in its last stronghold of Kent early last century and even an expensive and melodramatic plan by Sir Winston Churchill to reintroduce it at Chartwell was not a success.