Abstract
Two new species of the genus Melanoplus Stål 1873 are described. M. trachodes n. sp., and M. parvus n. sp., both of which are endemic to the cool-temperate mountains of the Eastern Sierra Madre (ESM) in northeastern Mexico. Their habitat represents a transition zone between the ESM and the semiarid High Plateau Biogeographic provinces. This transition zone is characterized by an elevation range from 1,900 to 3,400 m and unique ecological conditions, which give rise to a considerable number of endemisms.