So far as I am aware, the Genus Eysarcoris of the Family Pentatomidae is represented in Japan by six species which are, except for two rather rare species, well known pests very injurious to the rice plant, the soy bean and other various cultivated crops. It is considerably related to the genera, Carbula and Rubiconia, in which four species are known in Japan. Among these ten species, the larval stages of Rubiconia intermedia (WOLFF), Eysarcoris guttiger (THUNBERG) and Carbula humerigera UHLER have already been reported by the author (1951, 1953, 1956), but Carbula crassiventris (DALLAS), Rubiconia sp. and Eysarcoris melanocephalus (FABRICIUS) have not been studied yet. The developmental stages of four other species of the Genus Eysarcoris, E. parvus UHLER, E. lewisi (SCOTT), E. ventralis (WESTWOOD) and E. fallax BREDDIN, together with their ecological notes, are described in this paper. The diagnoses of the Genus Eysarcoris Egg: Short elliptical, light brown, with three dark rings, of which one is on operculum and two are on the side wall. Chorion white, with conspicuous large reticulations which is furnished with stout spines. Micropylar projections white, comparatively long, clavate, somewhat curved interiorly. Egg-burster mostly light brown except brownish central portion, well-chitinized T-shaped, of which the axis is not tapering inferiorly, the arms are tapering laterally, and membranous appendages are entirely translucent. Egg-mass ordinarily consisting of about 4∼14 eggs, arranged in two rows or sometimes in one row. Larvae: Stigmata placed each interior to connexivum of abdominal segments from second to seventh. Body rather elliptical in the 1st instar, rather ovoid in the 2nd to 4th, and elliptical, considerably angled at the humeral portion in the 5th instar. Body above sparsely furnished with short hairs, impunctate in the 1st and punctate in the 2nd to 5th instars. Median lobe longer than lateral lobes except the 5th instar of E. parvus UHLER in which it is about as long as lateral lobes. Lateral lobes without clear projections anterior to eyes, antero-lateral portion quite evenly arched in the 1st instar, subtruncate in the 2nd and 3rd, and truncate in the 4th and 5th instars. Posterior angle of pronotum nearly adjacent to the anterior angle of mesonotum. Thorax serrated laterally in the 2nd to 5th instars. Abdominal dorsal plate of the anterior odoriferous gland orifices wider than the plate of the median orifices in the 1st and 2nd instars, while the former is as wide as or narrower than the latter in the 3rd to 5th instars. The dorsal plates on the 1st and 2nd abdominal segments distinct in the 1st to 4th instars except E. lewisi (SCOTT) in which they are absent or indistinct in the 3rd and 4th, and absent in the 5th instar. Key to the species of the Genus Eysarcoris 1 (6) Egg with two rather clear dark rings on the side wall. In the larvae except the 1st or the 1st and 2nd instars, the ground colour of abdomen nearly white or light brownish, each with a row of rather indistinct, small sparsely punctate yellowish white spots and a rather wide, obscure, densely punctate, greenish, brownish or reddish longitudinal streak somewhat interior to connexiva. 2 (5) Egg about 0.9∼1.0mm in length, with micropylar projections which are about 32∼35 in number. In the 2nd to 5th instars, punctures on the body massive, a metallic luster indistinct (E. parvus) or partially faint (E. lewisi). Posterior angle of pronotum considerably developed and pronotum nearly as wide as mesonotum in the 5th instar. 3 (4) Egg about 0.9mm in length, with micropylar projections which are about 35 in number. In the 3rd to 5th instars, lateral margin of pronotum whitish except the posterior portion, mesonotum with a pair of white spots.
The writer and his co-worker (1959) described the larva of chrysomelid-beetle attacking the root of rice plant under a scientific name of Donacia simplex FABICIUS. Recently Dr. Michio Chûjô kindly suggested me that the scientific name the writer adopted was misused and the correct one should be Plateumaris sericea LINNÉ. The 8th abdominal segment of the female of Plateumaris sericea LINNÉ is very hard, dark brown and shows peculiar form. The tergite tongue-like, somewhat smaller than sternite. The sternite shovel-like and the terminal sharply pointed. It seems that the 8th abdominal segment of the female has a special usage in oviposition and the oviposition-habit of the species differs remarkably from that of other groups.