Tim Holschlag in his excellent book, Smallmouth Fly Fishing, 2005, divides bass flies (specifically smallmouth) into two types based on stimuli.
- There is the "Supernormal" fly like a nosiy topwater or a subsurface fly with wildly undulating tail or swimming legs.
- There are "Subtle" flies like a quiet topwater or a small natural -hued subsurface fly.
He goes on to look at fly descriptions:
- Depth: Is it a topwater, or a shallow-runner, or is it best fished mid-depth or near the bottom?
- Action: What does it primarily do in the water? For topwaters, does it pop, dive, buzz, slide, dart, or is it a dry fly? for subsurface flies, does it undulate, hop, swim, wiggle, or have other distinctive motion?
- Weight: If it's weighted, how heavy is it? The ounces in the head or the number and size of lead wraps in the body.
- Profile: Its overall shape -- bushy, bulky or sleek.
- Color: The primarily colors of hed, body and tail, or belly and back.
- Body Material: Its primary compostion -- cork, foam, chenille, hair, etc.
- Tail Material: Marabou, rabbit strip, hair, feather, silicon, etc.
- Extras: Any extra features not already listed -- legs, wing, rattles, large eyes, etc.
- Length: Total length of the fly in inches.
- Hook Dimensions: The hook shank length (hook eye to bend) and the hook gap (point-to-shank distance).