Tricorhythodes….sounds kind of monster-ish or even dinosaur-ian. That’s right folks, fishing for trout when this mayfly is on the water can be down right terrifying. In order to catch the action it requires an early start, the tippets are light and the flys are small. Trico’s are a prolific bug that are present on virtually every trout stream in the country. The streams in the St.Croix Valley are no exception. There have been times where I have caught fish after fish and returned the next day only to be completely baffled. Depending on the summer, they show up in July and remain a morning constant through September.