1)Grass spiders generally prey upon larvae of Hyphantria cunea DRURY. When these larvae shift from aggregation to the independent life, many larvae shift in high speed on thin branches and some on them lose footing and fall down like rain fall. These larvae fall on sheet like nests of grass spiders and spiders prey upon them. The shifting of these larvae is performed in the night. 2)Where Hyphantria cunea DRURY is distributed, grass spiders are also distributed. 3)Since the individual of grass spiders is too many, it is possible to collect its required number for affected mulberry farm in a short period of time. 4)Although the breeding of grass spiders is possible, it is hard to reproduce many at the present stage. 5)Grass spider does not harm on the growth of mulberry trees. 6)In the chemical spray, grass spiders escape quickly to the tunnel made at the end of sheett like net so that few of the are killed. 7)Because in the mulberry farm the number of grass spiders is not enough to control Hyphantria cunea DRURY in natural condition, we should liberate grass spiders each time. 8)When grass spiders are used as a predator for Hyphantria cunea DRURY we can not control entirely but we can reduce the damage slightly. 9)When we liberate a reasonable number of grass spiders in the mulberry farm every year, we can get a successful result as reported in this paper.
A description of a meagerly known whip-scorpion species, “Trithyreus sawadai KISHIDA, 1930”, which is now regarded as a species of the genus Schizomus, is given for the first time. In spite of insufficient original treatment which was presented only by figures, the specific name has still validity in the Zoological Nomenclature. Originally this animal was found from “the Bonin Islands”, but this time it was exclusively discovered from Chichi-jima Island in the same Islands. It may be allied to “Trithyreus” luzonicus HANSEN known from Luzon in the Philippines, but can be distinguished by the shape of flagellum of both sexes from all the other “Trithyreus” hitherto known.