The Motor Oil Chironocone Fly is used specifically for targeting trout in still waters such as lakes and ponds. It is designed to imitate the pupal stage of a chironomid, a type of midge that is commonly found in these bodies of water.

The fly gets its name from the color of the chironomid pupae, which can range from brown to olive green to a dark, metallic color that resembles motor oil. The Motor Oil Chironocone Fly mimics this coloration with its brown and green hues, as well as a metallic beadhead that adds weight to the fly and helps it sink quickly to the appropriate depth.

The fly is tied with a tapered body that resembles the segmented body of the chironomid pupa, and a prominent white or clear wing case that imitates the gas bubble that forms as the pupa rises to the surface of the water to hatch. The wing case also helps the fly to stand out and be visible to the fish, making it more likely to be taken.