Coleoptera: Elmidae & Dryopidae (Riffle Beetles)
- Dark, hard-shelld, tube-shaped larvae with leathery appearance.
- 3 pairs of jointed legs, each with a single case.
- End of abdomen with trapdoorlike operculum that can close over anal gills.
Length: 1 mm to 10 mm
Adults:
- Small, slightly elongate, hard-bodied, dark-colored beetle that may have yellowish markings.
- Long legs, each with 2 large claws.
Length: 1 mm to 8 mm
Peter Chen.