If you time it right, you can have some of the best fishing of your life fishing with live cicadas. Cicadas may be dormant for many years, then suddenly one year you can't even hear along the river because their buzzing is so loud. Trout will gorge themselves on these meaty insects whenever they can.
Cicadas can be picked from leaves, branches and trunks of trees near rivers and streams, when they are available. Don't worry, they won't bite you! :-) They are usually large and firm enough to stay on a hook quite well. Just remember not to use them in any stretches of steams that are artificial flies and lures only. In that case, use cicada imitations with your fly rod for a similar effect.