In Japan, the soy bean pod borer, Grapholitha glycinivorella MATSUMURA, is widely distributed and seriously infests the soy bean pod. However, this insect pest has been little known in the southern half of the country so far. This paper gives an account of both laboratory and field observations on the seasonal occurrence of the borer and the damage caused by it. The observations were conducted at Kanto-Tosan National Agricultural Experiment Station, from 1955 to 1959 inclusive.
The first brood moths commenced the emergence in the middle of July and showed the peak emergence at the beginning or in the middle of August. The second brood moths emerged from the middle of September to early October, although less in number than the first.
The seasonal fluctuation of the number of eggs investigated in the field at about five day interval, almost coincided with the fluctuation of moth population. Two peaks, one in the middle of August and the other at the end of September or at the beginning of October, were observed. The first brood larvae were found from late July or from early August, and their number increased rapidly, reaching the peak at the end of July. Then the population of the first brood inclined. The second brood larvae were observed from October to November, but in small number. This minority of the second brood seems to be attributable to the greater environmental resistance caused by the low temperature in autumn, or the poor ripening of late varieties of soy bean which serve as the host plant of the second brood larvae.
To study the hibernating ratio of the first brood larvae, matured larvae were collected periodically in the field. The hibernating larvae were found from the batches collected at the beginning or in the middle of August. All the larvae collected in the middle of September hibernated. Thus the existence of the partial second brood is evident in this district.
The existence of just one brood of this pod borer is known in the area north of Tohoku. district, but the partial second brood seems to exist in the area south of Kanto district. The second brood seems to be more dominant in the warmer region.
The damage caused by this pod borer differs considerably by the soy bean varieties. The earliest varieties escape from the attack by the first brood larvae, while the early and middle varieties are damaged to a greater extent by the attack of the first brood larvae. The late varieties are less damaged by the larvae of the second brood.

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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.

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Since the larvae of the peach fruit moth, Carposina niponensis WALSINGHAM, eat into fruits just after hatching from eggs, it is difficult to distinguish the instars in the larval stage. In the present paper, an attempt was made to determine the instar of the larvae which were reared under a constant temperature in the laboratory as well as collected in fields by measuring the width of the head capsule. The results obtained are summarized as follows:
1. In both the first and the second broods, the frequency distribution of the width of head in the laboratory samples is composed of four independent mountain-shaped curves, which correspond to the four different instars of the larvae. This is also the case in the larvae collected from fields at random.
2. The ratio of the mean head width between each instar and the preceding one, which is sometimes called growth ratio, shows a tendency to diminish slightly with advancing age in the first brood. But no uniform tendency is found in the second brood, and the ratio between the second and the third instars is largest.
3. When the larvae of the first brood are fed on the fruit under a constant temperature of 22±1°C, the larvae complete their development in 15 days. In the second brood the larvae complete their development in 17 days at 21±2°C.
4. Three formulae for growth, DYAR'S, TOKUNAGA'S and GAINES & CAMPBELL'S formulae, were examined for their applicability to the present case. It was found that GAINES & CAMPBELL'S formula best fits the case.

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The main object of this work is to ascertain whether there is any effect of food plant on the appearance of certain density dependent variations in the larval and pupal stages.
The young leaves of seven different plants, goosefoot (Chenopodium centrorubrum), cabbage (Brassica oleracea var. capitata), Pak-Choi (B. chinensis), Chinese cabbage (B. pekinensis), redradish (hatuka-daikon; Raphanus sativus var. macropodus), spinach (Spinacea oleracea), and potato (Solanum tuberosum) were prepared as the food for the larvae. Hatches from an egg mass deposited by a female were kept at densities of 10 larvae per glass tube (200cc) as crowded culture and 1 per tube (50cc) as solitary culture on every food plant. The rearing experiment was conducted in a thermostat at 25°C and darkness.
The results are summarized as follows:
1. The 5th instar larvae of the solitary culture showed great diversity in colouration, possibly related to the quality of food plant, while in the crowded culture, it was not great and the darker larvae were predominant on every food plant. This indicates that whatever influence food plants might have on the body colour of the larvae, it was overshadowed by the influence exerted by crowding.
2. Crowding induces a more rapid development on goosefoot, cabbage, Pack-Choi, Chinese cabbage, red-radish and spinach, and a more slower development on potato. The mean duration of larval stage in the crowded cultures was highly variable between the batches fed on different food plants compared with that in the solitary cultures. From these results it might be considered that the effect of crowding in accelerating development was not constant, being influenced by the food plant.
3. The lower the favourableness of the food plant the lower was the mortality caused by crowding in the larval stage. In this case the sex ratio indicates that females suffered from a higher mortality than males.
4. Though the crowding in the larval stage produced smaller pupae on every food plant, the effect of larval density on pupal weight varied with different food plants.
5. The ratio of diapausing pupae was fluctuated from 0 to 40 per cent among cultures. But, in this case, the larval density had no conspicuous effect on the production of diapausing pupae.

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Many authors in Japan have thrown doubt upon the existence of pore canal in the silkworm larvae, because it was invisible in ordinary paraffin sections. However, when the fresh sections cut with freezing microtome are examined in water under a light microscope, pore canals are clearly seen penetrating through both the exo- and the endocuticular layers of the larvae. Arising directly from the epidermal cells all the canals (2∼4μ in diameter) run a parallel vertical course in deeper part of the cuticle, but near their middle part they branch off towards the surface (with an average diameter of 1∼2μ in a single branch). At the outer extremities the canals seem to reach beneath the epicuticle of each tubercle of the integument.
The epicuticle of the silkworm is not readily distinguished from its underlying exocuticle from the staining properties of the paraffin section examined by means of the light microscope. But both layers can be separated from one another, if the cuticle is examined under the phase-contrast microscope either in the freezing or in the paraffin sections even if they are not stained.

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Previously the author has reported in a series of papers that damages of the rice plant caused by the larvae of the rice stem borer, Chilo suppressalis WALKER, were reduced with increasing silica content in the rice plant by suppling silicate fertilizer into soils. This response seemed to be due to not only hardening of the plant tissue by absorption of silica but also feeding preference of the larvae between high and low contents of silica in the rice plants.
The present paper deals with the feeding preference of the larvae for rice plants grown in soils supplied with different levels of nitrogen. The method employed was of a two-choice design, in which the larvae were allowed to choose pieces of the rice plant stems, and also alcohol extracts of the rice plants absorbed in filter papers.
The larvae preferred singnificantly the high nitrogen plants to the low nitrogen ones. Similar preference was observed for alcohol extracts between two kinds of the rice plants; the extract of high nitrogen plant was more attractive than that of low nitrogen plant for the larvae.
It is a well-known fact that the plant containing high level of protein in injured severely by the larvae. The present experimental results may indicate that nitrogen fertilizer affects not only nutritional aspects, but also synthesis of attractive substances, both olfactory and gustatory, for the larvae.

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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.

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1. A semiquantitative microautoradiographic technic was applied to the metabolic studies of protein as well as ribonucleic acids in the posterior silkglands during the fifth instar period of Bombyx mori.
2. Actually no incorporation of ³²P or ¹⁴C-glycine into deoxyribonucleic acid was observed. Whereas, a remarkable renewal of RNA-³²P was shown around 2nd and 3rd days of the fifth instar. Later the incorporation of ¹⁴C-glycine into fibroin began from the 3rd day and reached to a maximum at the 7th day. These observations led to the conclusion that the co-synthesis of ribonucleic acid during the fibroin biosynthesis is not required.
3. Different sites of the incorporation of ribonucleic acid were observed in the different labeled compounds: ³²P was incorporated rather in external area of silkglands, whereas ¹⁴C-glycine was incorporated solely into the nuclear RNA. Both labeled compounds did not enter into the RNA-core after RN-ase treatment.

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The neurosecretory cells of the brain and the secretory cells of the corpora allata in the rice stem borer have been investigated histologically through diapause and post diapause.
The neurosecretory cells of the brain consist of three groups in each half of the brain, medial, lateral and posterior groups. The posterior groups may be of new record in the brain of lepidopterous larvae. The medial group comprises two types of neurosecretory cells, A-cells and B-cells.
The histological appearance of the B-cell changes remarkably with the progress of diapause break, i.e., the B-cell looks like inactive during diapause period and becomes active towards the termination of diapause. The other neurosecretory cells did not show any significant change during that period.
Judging from the histological appearance as well as the volume changes of the corpus cardiacum and corpus allatum complex the corpus allatum seems to show high activity during diapause and to lose its activity gradually towards the pupation.
It may be noteworthy that there is a close relation between activities of the corpora allata cells and the B-cells of the brain during diapause and post diapause.

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