Horsehair Worms (Phylum Nematomorpha) in Wisconsin, With Notes on Their Occurrence in the Great Lakes

Abstract
Wisconsin records for Chordodes morgani, Gordius robustus, and Paragordius varius are summarized. The occurrence of horsehair worms in the Great Lakes Is reviewed. Sexual size differences are demonstrated In G. robustus, with females being significantly longer than males. Skewing of sex ratios in horsehair worm populations is discussed.