- very small - 6 legs - size range: 1/16" - 1/8" - may be found in larval form (this form is not counted in the assessment)
Riffle beetle adults are very small and hard to spot because they are dark colored (usually black) and blend in well with chips of slate and dead leaves in the seine. To find these beetles, watch the seine closely for movement. Be careful not to mistake small terrestrial beetles for riffle beetles. If you are uncertain if you have a riffle beetle or a terrestrial beetle, put it in water. If it seems well adapted to water and fits the rest of this description, it is probably a riffle beetle. Please be aware of the appearance of the larval form so you do not confuse it with other organisms. Note: The larval form's hard exterior, cylindrical shape and the small tuft of white filaments which are present at the rear of the organism.