Detailed descriptions and illustrations of Erpetogomphus agkistrodon Garrison, E. erici Novelo and E. ophibolus Calvert are provided and a comparison with other larvae of the subgenus Erpetocyclops Carle is also included. Larvae of E. agkistrodon and E. erici show the closest resemblance, while E. ophibolus is more similar to E. constrictor.