Illustrated key to nymphs of the tick genus Amblyomma (Acari: Ixodidae) found in the United States.

A dichotomous identification key, with important characters illustrated by scanning electron micrographs, is provided for nymphs of the 9 species of the genus Amblyomma occurring in the United States. Species included are A. americanum (L.), A. cajennense (F.), A. dissimile Koch, A. imitator Kohls, A. inornatum (Banks), A. longirostre (Koch), A maculatum Koch, A. rotundatum Koch, and A. tuberculatum Marx. Notes on the geographical distributions, medical and veterinary importance, and nymphal stage hosts are included for each species.