The larva and pupa of Asynarchus contumax are described for the first time, and compared with these of A. lapponicus. The two species live in temporary and permanent pools and have one year life cycles. Emergence and flight periods of both species were restricted to late June and early July in a pool with a short drying-up period. The flight period of A. lapponicus in a permanent pool was from early July to early September. A. lapponiclls was the dominant species in pools above the tree line, in the 1ow alpine belt, whiter, contumax was dominant in the sub-alpine belt. Neither species had an imaginal diapause. The active life of A. lapponicus and A. contumax, e.g. larval growth, pupation, emergence, mating, egg maturation, and oviposition, lasted 3-5 months, and 7-9 months were passed in a passive stage, probably inside the gelatinous matrix. The egg-masses laid on dry ground in basins during July-August were exposed to air temperatures of -20 to -30°C in late autumn in 1979, but larval hatching was normal next spring.