Although Brachycercus nymphs seem to prefer silt bottomed slower water, I've found them hatching in some pretty fast currents. A pretty good indicator that they drift for a good distance before emerging. Easily mistaken for a large Trico most hatches take place in the evening. Spinners can be found both in the evening, and mixed with Tricos during the morning. Similar to Tricos, Brachycercus duns have almost white, or dirty white forewings and lack hind wings. Their bodies are dark brown almost black with a light gray or dirty white abdomen. Like Timpanoga simplex this is another overlooked mayfly that produces very fishable evening hatches.