Montana Field Guide

Neophylax caddisflies are a medium-sized insect (~3/4-1 inch) and adults which resemble moths, but fold their wings tent-like above their backs are commonly known as Autumn sedges. As larvae they are scrapers of algae and diatoms from cold river bottom rocks and cobbles, and emerge in concentrated numbers in the fall because they enter a pupal diapause within their rock/pebble cases during mid-summer (Diapause: A state of complete dormancy deeper even than hibernation. While in diapause, an organism does not move around, eat, or even grow). Some caddisfly larvae enter diapause for a few weeks to several months during the summer, which synchronizes their emergence to within three weeks on a given stretch of stream.