Aeropedellus clavatus (Thomas), an alpine and boreal grasshopper, is resident at higher altitudes in the Colorado Rockies than any other acridian. A 5-season study of an alpine population sampled at 12,800 and 13,100 ft above sea level on Mount Evans, Colorado, involving 2838 specimens (including 1734 juveniles), revealed various adaptations to an alpine habitat: an abbreviated life cycle—only 4 juvenile instars; hatching while ice and snow are still present in the immediate surroundings, and sexual maturity reached in approximately 6 weeks thereafter; oviposition in basal portions of sedges and grasses; diapause apparently involving more than 1 season; feeding predominantly on sedges and grasses. The eggs and egg pods, and the various stages in development of both sexes, are described and illustrated.