I think Hans has it right. I think the mayflies were Hendricksons. They are one of the best hatches of the year and they are presently in full swing. The female spinners return to the stream about dusk to lay their eggs. You will see them dipping their tail in the water to dislodge the eggs from the egg sack at the end of their tail. You will often see fish jumping out of the water at the tail of a pool trying to catch them while they are hovering and egg laying.
I tie a couple of simple parachute patterns to imitate them. I use pink thread and hendrickson pink superfine for the body with a yellow egg sack. I tie both with dun hackle. Light or dark dun, it doesn't seem to matter. Use pink or red thread, it enhances the pink color when it gets wet.
The other one I use a tan biot and some pink superfine for the thorax.
So get you some pink thread and some hendrickson pink superfine dubbing.