The body of the nymphs are not strongly flattened and appear somewhat minnow-like. They have gills on segments 1-7, lack mandibular tusks, and have double front tarsal claws. The outer pair of tails have hairs on inner side only.
Adults have 2 tails. The lateral ocelli are 1/10 to 1/4 the size of the compound eye. The hind tarsus has 3 or 4 clearly defined, moveable segments. Abdominal segments 6 and 7 are not wider and higher than the adjacent segments. The forewings of the adults are heavily spotted, have one or two pairs of long parallel cubital intercalary veins, and lack free marginal veinlets. Forewings lack long intercalary veins between MP2 and CuA and vein MP2 is not bent near its base. The hindwings are relatively large and are spotted.
These mayflies are relatively uncommon and of little importance to the fly fisherman.