Mother’s Day is more than a family event, it’s when peak emergence occurs for the caddisfly Brachycentrus occidentalis, aka. the Mother’s Day caddis.

Riffles and runs with softball to bowling ball sized cobble provide ideal habitat for B.o. larvae.

The chimney-shaped cases of B.o. larvae are attached to the upper surface of a cobble stone, where they hold their legs up into the current to feed.

Where conditions are right B.o. larvae can occur in huge numbers.

This pupa shows the bright green abdomen of B.o. pupa.  The pale wingpads also indicates that it’s not fully mature.  Wingpads on mature pupae will be almost black in color.

Dark gray to black is the dominant color for B.o. adults.  If seen up close you will also notice a small green band along each side of their abdomen.  Most adults can be imitated with a size 16 dry fly. (photo by Dave Hughes)

Hatch activity is commonly concentrated in and below choppy riffles.  Trout will often be showing splashy aggressive rises as the chase after swimming pupae.

Rainbows and browns are get equally excited when B.o. are emerging.  Remember to not strike too hard when setting the hook, especially on a large trout.

Patterns for the Mother’s Day caddis should include larva, pupa, and adult, though this time of year the larva pattern will be of little value.