This plant is from a great location in Grey Co., ON where unusually many veinless and antho-free purpurea occur beside the typical red form. I think that's the site @H2O presented some years ago elsewhere or at least it's a similar site. Some of the most extreme veinless plants found there are very hard to tell apart from antho-free plants because they produce so little red pigments that they even have yellow flowers. They lack the red pigments in the petals, too, but they are able to produce at least some anthocyanins as the slightly reddish grow point shows.
The pictured plant was grown from selfed seed of a plant labelled 'veinless, yellow flower'. Obviously this offspring is not completely veinless. Older pitchers show some fine veins, so I would rather call it 'semi-veinless'. But others (McPhersons/Schnells (2011, p.453)) would still call this a veinless plant, because it stays very green even in full sun. The flower is very pale red, and not yellow as I anticipated. The lower side of the petals is whitish with no red, the upper side is patchy pale purplish, especially where exposted to the sun. Shaded parts of the petals are very pale. Maybe some other seedlings that are still juvenile will perform a bit better. But even though or maybe because it is not perfectly veinless and yellow flowered it is an interesting and nice plant.
I've shown earlier some truly veinless plant from neighbouring Huron Co., ON, that has a similar or slightly darker flower.
And another one, also from the location in Huron Co., ON, that has pitchers with similar light veins, but a much darker flower. The young, still growing pitchers of this one are more pinkish than the other two.