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    Key to Aquatic Macroinvertebrates in Utah - Coleoptera

     Water Beetles

    The Coleoptera Order


    Amphizoidae (trout stream beetles)

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    DescriptionLarvae are elongated, with flattened lateral projections, and 2 short spine like cerci (tails). Adults have a broad appearance and are reddish brown to black. Length 10-15mm.

    HabitatIn cold mountain streams. Adults are often collected near the surface in eddies and on twigs and aquatic plants. 

    Dryopidae (long-toed water beetles)

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    DescriptionLarvae have clinging legs with large claws and clubbed antennae. Adult bodies are hard and the head is nearly drawn into the thorax. They have a short, thick antennae. Length 5-10mm.

    Habitat: Larvae are terrestrial. Adults are typically found in stream riffles and along stream margins. Only 1 genius Helichus have been collected in Utah.

    Dytiscidae (predaceous diving beetles)

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    DescriptionLarvae are elongated and spindle shaped with oar-like hind legs and 2 cerci (tails). Their heads are large with a large anterior prolongation (constriced neck). Adults are ovoid shape x-section and are shiny, brown, black, greenish, or yellow with and without spots. Adults have long antennae. Length 10-40mm.

    HabitatAdults and larvae are found in slow moving streams, ponds, wetlands, and lake littoral zones.

    Elmidae (riffle beetles)

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    DescriptionLarvae have stiff, cyclindrical bodies. They have a single claw and a filamentous gill on their last abdominal segment. Adults are small, hard-bodied and their heads are slightly withdrawn into their thorax. Their legs are long and have 2 claws. Length 2-8mm.

    HabitatFound only In rapid moving fresh water.

    Gyrinidae (whirligig beetles)

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    DescriptionLarvae have elongated slender body with long lateral respiratory filaments on abdomen, and 2 pair of hooks on last abdominal segment. Length 10-30 mm. Adults may appear to have 4 eyes (1 pair looking down and 1 pair looking up. Adult bodies are black, shiny and oval. Length 3-10 mm.

    HabitatIn still and rapid moving fresh water margins.

    Haliplidae (crawling water beetles)

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    DescriptionLarvae have an elongate, sclerotized body, two terminal filaments at the posterior end of abdomen, and some species have long dorsal projections of hairs or spines along their abdomen. Adults have small heads, a plate that covers their hind legs, and skinny legs. They are often yellow with black markings. Length 2-8 mm.

    HabitatIn ponds and stream pools. They are typically found in riparian debris and aquatic plants crawling along sticks and plant stems.

    Hydrophilidae (water scavenger beetles)

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    DescriptionLarvae have large toothed jaws that are readily visible from above.  They have four segmented legs. Adults have clubbed antennae and are often confused with dytiscidae. They may have a metasternal spine or keel. Length 2-40 mm.

    HabitatFound in a variety of aquatic habitats.

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