Dave's Hopper is the classic grasshopper pattern, and this hi-vis foam version from Dream Cast Fly Fishing adds buoyancy and visibility. The foam body floats all day through the roughest water.
Fish it on a dead drift along grassy banks in late summer, with an occasional twitch to suggest a kicking hopper.
Late summer is prime time for terrestrials, especially on windy afternoons when the breeze knocks insects off the bankside vegetation.