Abstract
The habitats of two praying mantises, Tenodera aridifolia and T. angustipennis, comprised different parts of grasslands in central Japan. The life histories were investigated in the habitat where each species was predominant. Egg hatch, nymphal development and adult emergence of the larger mantis, T. aridifolia, occurred earlier than those of the smaller congener, T. angustipennis. These three aspects of development of the former species were more divergent in timing than those of the latter. Durations and survival rates of nymphal and adult stages were slightly longer and higher, respectively, in T. aridifolia than in T. angustipennis.
