I would not like to have to match this hatch. These are the smallest mayflies I have ever seen. I used to think Caenis
was the smallest adult mayfly in the west but these guys are about 4mm long. The male eyes are two toned, brown above and olive below. The abdomen is dark brown interspersed with light brown. The abdomen is clear for the anterior
2/3rd and the remainder is white. The tails are twice as long as the insect. There is only one pair of wings.