What H-A says is usually the case. They come off sometimes as early as 3rd week of June. But don't count on that. Also the Ltl. Blue Quills start in early June and have the same hatch period as Tricos. They appear to be tricos and in fact many anglers mistake them for tricos. They are much thinner bodied then tricos. Tricos are #24 and LBQ's are usually 20 to 22. LBQ's also have a central body that is clear or white.
Chaz,
I never knew of LBQs on the LL. I can see how I mistook them for tricos. Is this hatch significant to the FFer, normally? I was out Sunday AM and took some fish on trico patterns that seemed to be feeding on spinners, although I knew tricos start later. Just curious...
Actually it is important if the trout are taking the LBQ's and not tricos, and trust me, they do know the difference. Because when they are taking one they won't be taking the other.
The biggest difference is that tricos hatch during the overnight hours and the early morning getting late as the season moves along.
The LBQ hatch in the morning, but the spinners come back during the evenings.
On a side note, I was standing at where the dam USED to be right above Heritage section, and it was great to see some seams and nice pockets with bugs flying everywhere. Much better, imo.