Dichotomous Key

Dichotomous keys make it easy to identify your critters by asking you simple questions about the critter's morphology (shape) that lead you to the species name.

Thanks to the University of Virginia and the Save Our Streams Program of the Izaak Walton League of America, this dichotomous key link is available for you to use.
http://www.people.virginia.edu/~sos-iwla/Stream-Study/Key/Key1.HTML

The Stream Biomonitoring Unit of the New York State Department of Environmental Conservation provides this online macroinvertebrate key with representative photographs of major groups of aquatic macroinvertebrates. http://www.dec.state.ny.us/website/dow/stream/index.htm