The role played by Polistes wasps on the natural control of agricultural and forest pests seems to be very important. This report shows the author's observations on the hunting activities of Polistes chinensis antennalis Perez which were nesting in natural conditions. The prey which are hunted by Polistes wasps for breeding their larvae are not restricted to some specific species or species groups, and if the insects are of adequate size having the habits of adequate mode of life, they are generally chosen as the wasp's prey. Among the prey many important pest insects are included. In Polistes wasps there seems to exist no considerable differences between the number of flesh pellets which are carried into the nest and that of the prey. Accordingly, it is possible to estimate the approximate number of prey by observing the frequency of carrying the flesh pellets. According to the author's observations on the nests just after the emergence of newly hatched larvae or before the emergence of the worker caste, a founding female of Polistes carries the prey five times a day on an average. As the duration between the first emergence of larvae and the emergence of the first workers is about 30.4 days, an estimated number of carrying prey per one nest is about 152. After the emergence of the workers the number of carrying prey increases rapidly, amounting about 28.8 times a day. It takes about 70 days from the emergence of the workers to the cessation of the nest's development. Therefore, the total number of prey carried during this period seems to be estimated as over 2000 prey. The author's observations reveal that the Polistes wasps are very valuable in utilizing them as an important natural enemy of agricultural and forest pests.
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