The last abdominal segment bears a pair of fleshy appendages with hooks. Adults are terrestrial and resemble small moths. Note the head and legs emerging from the case on the right side of photograph. Photo courtesy of Ken Fritz. In terms of species, this is the largest and most widespread group of stream insects.
Adults are terrestrial and often resemble mosquitoes.
Figure 8 . Note the brown head and single fleshy proleg. The swollen area on the left is a modification of the abdomen that aids in movement. Photo courtesy of Lara Panayotoff. Note the small yellowish head and single proleg on the left.