Tails and antennae are same length.
Blooming under water in mats, in slow moving stream. Leaves covered in algae.
I am not sure which variety of phlox this is. The leaves where not sticky as several varieties of phlox are described....so I am guessing it is the "spreading phlox". Also, many of the flowers were pink, and purple which is described in the Laws Field Guide as indicating pollination.
Beside letharia vulpina
Yellow stripes down back on either side
Pistil longer than stamen
Long Compound leaf
thick stems supporting flowers
About 3ft tall
Flat leaves, wider leaves lower
Leaves mostly at base