This is the Great Pumpkin of Western rivers, a caddis that is almost as large as a golden stonefly. As the name suggests, it emerges in fall.
October caddis larvae build cases of small pebbles and live in moderate to fast flows. As a larva grows, it will abandon its case and build a new one. In the process it may get knocked lose and drift in the current. Even cased larvae sometimes end up in the drift, especially when they migrate to slower water in June and July. Where there is a large population of October caddis, it is not unusual for trout to eat drifting larvae, with or without the case. So a cased caddis pattern dead-drifted near the bottom a worthy strategy beginning a couple of months before the hatch season.
As it nears maturity, the larva will seal off its case and pupate. Many pupae emerge in water that is not very trouty, but a few come out where fish are found. Since this is such a big bug, it doesn’t take very many of them to capture the interest of trout, and the fish will be looking for them. When you see adult October caddis around, it’s worth drifting a pupa pattern near the bottom.
Adults survive for a couple of weeks after they hatch, and trout can be quite eager for them. The caddis are blown out of bankside vegetation and land on the water, and females return to the water to drop their eggs on the surface. At these times, a dry fly can be very productive. What fly angler can resist this final opportunity of the season to cast a large dry fly?
Link (Via: West Fly)