At the beginning of the dotothea hatch it's not unusual for all three sulphur hatches, Ephemerella rotunda, Ephemerella invaria, and Ephemerella dorothea, to overlap. During this period the fly fisher may find sulphurs on the water from size 12 to 20. Dorothea nymphs prefer slow to medium current, and prefer hatching in water temperatures between 45 and 55 degrees. In warmer water temperatures they will wait until late evening or even after dark for the water to cool before beginning to hatch. On the west branch with steady cold water releases from the Cannonsville reservoir dorothea can be a major hatch from mid June all through July, and into early August. On the upper east branch where the flow from the Pepacton reservoir are much more consistent dorothea can be a major factor for the fly fisher from mid June all thru August. Spinners are very pale yellow, some are almost white.