Picked on July 31.
BTW, the Diva cucumber on the bottom is the only cuke I've gotten from these plants this year. But two days ago I figured out why: there are no male blossoms on the plants! Lots of tiny cucumber ovaries that are not fertilized.
So I brought over a male blossom from my other patch of cucumbers. Before I could do the deed myself, a honey bee landed right on the flower in my hand! It stayed a bit and then flew over to one of the female flowers. Believe it or not, today I noticed that a cucumber is finally growing there!!