This guide was designed to aid Illinois RiverWatch Citizen Scientists to identify stream macroinvertebrates. Only those stream indicator taxa used in the assessment of stream quality by Illinois RiverWatch are listed in the is guide. Not all macroinvertebrates collected can be identified with this guide. The use of these organisms for stream quality assessment is restricted to the state of Illinois.
Size ranges given in the pictures are for mature individuals.
Turbellaria Soft bodied, flat and non-segmented worms. Gray, brown or black, often molted, striped or spotted. Ventral sides gray. May have two dark eyespots on the dorsal side of the head. Body markings gray and the eye spots white in preserved specimens.