Riffle beetles are very small and hard to spot because they are dark colored and blend in well with stones and dead leaves. They are pollution sensitive organisms that cling to stones and feed on plant material. The Curculionidae beetle pictured below is considered semi-aquatic, often found chewing up leaves or boring into stems above the water surface.
  Optioservus and Stenelmis larvae are usually not found in great numbers in the River, however, they have been found as far downstream as South Scranton. The greatest numbers have been found through the Mid Valley downstream to North Scranton. Curculionidae organisms are rarely found, most likely because they are not truly aquatic.

	Family: Elmidae Genus: Optioservus
	Family: Elmidae Genus: Stenelmis
	Curculionidae