The leeches of Ohio consist of 2 orders, 6 families and at least 27 species. Despite their reputation as "bloodsuckers" only a small minority of U.S. species will take blood from warm-blooded animals (Smith, 2001).
Leeches are often confused with Turbellaria by the beginning collector but can be distinguished by lacking the arrow shaped head and eyespots of the latter. Leeches also have a distinctive locomotion, stretching out to enlarge their length during movement.