Using Aquatic Macroinvertebrates as Indicators of Stream Flow ...

• Dytiscidae (predaceous diving beetle): intermittent indicator; adults are dark, shiny, convexon top and bottom; may be patterned with lighter patches or fine stripes; up to 40 mm (1.6in.) in length; long slender antennae; hind and middle legs flattened, covered with densefringe of swimming hairs. Larvae have elongated bodies, long slender legs; often 2 smallcerci (“tails) at the tip of the abdomen; conspicuous broad heads with large curved mandibles• Hydrophilidae (water scavenger beetle): intermittent indicator; adults resemble Dytiscidaebut often have raised keel on underside of body; up to 44 mm (1.6 in.) in length; last 3segments of antenna swollen to form a club, and segment immediately preceding club maybe cup-shaped; Larvae have long cylindrical bodies with short legs; up to 60 mm (2.4 in.) inlength; strong curved jaws project at front of head; tip of abdomen is bluntly rounded, lackscerci.Odonata (dragonflies & damselflies)• Gomphidae (clubtail dragonfly): perennial indicator; body slightlyflattened, up to 42 mm (1.7 in.) in length; tip of abdomen roundedor tapering to blunt point; labium (lower “lip”) is flat, not scoop- orspoon-shaped; antennae have 4 segments, with 3 rd segment larger,conspicuous, often a different shape, 4 th segment small, barelyvisible• Cordulegastridae (biddies): perennial indicator; larvae may appear hairy; up to 45 mm (1.8in.) in length; labium (lower “lip”) is scoop shaped and coversmuch of the front of the head when not extended; short threadlikeantennae with 7 segmentsMacroinvertebrates as indicators of stream flow duration,The Xerces Society for Invertebrate Conservation32