Carl the Caddis Fly LarvaCarl is a bug with a recognition problem. When he introduces himself as a caddis fly larva, most of the audience usually replies "what?" But as people are quick to learn, caddis fly larvae are great indicators of shoreline health. If the water is clean, you'll meet plenty of caddis flies. Look closely along a healthy waterway and you might just spot Carl or some of his kin!