First, I think we would all agree that Purple Midge Larva would be a great name for a rock band.
This is the first time I have seen these in pond dips. The ones I am showing here are moderately small, but I found broken corpses two and three times larger.
These are the bodies that impart the coloring.
I've seen the Bloodworm midge larva before, but the coloring extended to the shell and head of the specimen, not just these purple bodies.
Images made through a microscope. All subject types.