Riffle Beetles

Both the adults and larvae of Elmidae live in and around the shallow riffles of fast-moving streams. They are found under rocks and clinging to aquatic mosses and other water plants. Pupation takes place in cells under rocks or in moss on the shore of the stream. Species with fully developed wings take only one flight, for the purpose of dispersal. On this flight they may be attracted to lights.

The adults have a dense layer of short hairs that holds air that surrounds their body; the beetles appear silvery as they move in the water (Evans 2014).

Riffle Beetles are not tolerant of polluted water, thus their presence is an indication of good water quality.

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Stenelmis sp.
Stenelmis sp.