Pictorial key to the adults of hard ticks, family Ixodidae (Ixodida: Ixodoidea), east of the Mississippi River.

Six genera and 27 species of hard ticks (Ixodidae) currently are recognized in the United States east of the Mississippi River as follows: Amblyomma (4 species), Boophilus (1), Dermacentor (3), Haemaphysalis (2), Ixodes (16), and Rhipicephalus (1). We present a diagrammatic couplet key to the adults of the six genera and 27 species of Ixodidae found in the eastern portion of the United States.