Hendricksons light/dark a bit confusing

[Ant]

What is the true division of this mayfly.

In a new book I purchased by Ted Fauceglia "mayflies" he only lists Hendricksons.

Stating male (also the red quill) is simply darker and the female is lighter. Additionally theres the size difference between the 2

Also 3 tails or 2? His book has both as having 3.

I have seen so many differences through the web it's crazy. He classifies the Species as Subvaria. On this site I see 2 areas on the hatch chart: Hendrickson/red quill (subvaria) dark Hendrickson/red quill (rotunda) But no mention of light, at least I didn't see it.
Caucci has a "Ephemerella X" added in his with subvaria as the species

I'm guessing most of the confusion is due to reclassification.

I know the fish don't care but...I want to have it right.

BTW nice site.

Thanks
Ant