The life history of Cyspius orientalis YAGINUMA was studied during 4 years both in the laboratory and in the field. Mating was done suddenly without any premating behavior. The female laid eggs only once in a year. She made a lentil-shaped egg-cocoon and carried it with her spinnerets. She extended silk threads irregularly between stones in a small area, in which she protected the egg-cocoon for about a month. Then the spiderlings escaped from the egg-cocoon and clustered on the surface of the empty cocoon for a few days, during which the cocoon was still attached to their mother's spinnerets.
All the individuals matured at the 9th instar. They passed through the first winter as juveniles and the second as adults. Some adult females survived other individuals till the fourth year. The population studied has a 2-3.5 year life cycle.