In order to make clear the mechanism of the water loss through integument in the wireworms, Melanotus caudex LEWIS, the authors measured the speed of water evaporation from body, by exposing them in incubators under several conditions, and measuring the diminution of their body weights by torsion balance.
1. Decreasing tendencies of the curves of both the body weight and the body water, may be due to the decrease of body weight, which is equal to the evaporated volume of body water.
2. The speed of water evaporation from the body under a constant humidity (ca. 20% R.H.) was almost constant at 14∼20°C, and increased rapidly above 25°C. this tendency was very similar to the case of oxygen consumption. This leads us to the conclusion that any temperature over 25°C is unsuitable for growth of wireworm.
3. The speed of water evaporation from the body at 20°C increased linearly with the decrease of humidity. It is assumed, therefor, that there exist large areas which cannot prevent water evaporation on the integument.
4. By dipping the wireworm into ammoniacal silver solution, the abdomen sterna longitudinally along the basal line and also the base of legs in thorax sterna turned to black. The deoxidized parts on the integument seems to be polyphenol layers. Those parts are considered to be connected with the evaporation site.
5. When the leg movement stopped and worms became hard and cylindrical due to the water loss, they seemed to be dead but retained still an ability to burrow into soil when they were dipped into water for several minutes.
6. The curve of the evaporation speed had a shift at the midst of regression line where the ability of keeping their body water was lost.
Thus it became clear that the wireworms have a little ability to defend the water loss.
7. In winter period the speed of evaporation was about a half as that in spring period, and this tendency was almost the same to the cases of the resistivity against drying and dipping into water.
8. Under the condition of 20°C and about 20% R.H., the evaporation speeds of body water in other kinds of soil insects were compared with those of insects living in other environments. Larvae of Curculio dentipes and Tipula aino did not die by drying for 200min. The highest speed was that of Lacon fuliginosus, namely, 2.42 times as fast as in case of Melanotus caudex. Eevaporation speeds of both Popillia japonica and Melanotus caudex were almost the same.

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The prevention of insect pest injury to potatoes is always an important but difficult problem. As pointed out by the author in the preceding article (HUKUSIMA, 1956), insect pests were twice as abundant in monocrop field of potato as in intercropped field of potato and corn. Comparing the seasonal change of insect communities in these fields, it became apparent that the community of the intercropped field attained to a stable state earlier than that of the monocrop field and was poor in number. A few works have been done so far by several authors on the relationship of intercropping to insect populations, and it was reported that intercropping maintains insect population at low level. This decrease in population in intercropped field convinced that the tall intercropping plants which play an important role as a partition-wall are conducive mainly of a higher rate of prevention in the migration by small-sized insects. Except the large 28-spotted lady beetle (Epilachna vigintioctomaculata MOTSCHULSKY) which causes extensive damage to potato leaves, the insect fauna of the potato field is composed principally of small-aphids such as Aphis gossypii GLOVER, Aulacorthum matsumuraeanum HORI and Myzus persicae SULZER which widely distribute in northern Japan and the onion thrips (Thrips tabaci LINDEMAN). The high intercropped crops seem to serve to prevent the migration of these small insects. The work reported in this paper was undertaken with an aim to draw some definite conclusions on the causes which induce an increase or decrease of certain insects and to treat the difference between the insect communities of the potato field and the potatocorn intercropped field.
In 1956, the observations were made on two adjacent plots 6 by 12 feet in size. Potatoes and corns were sown on April 29th ridging in eastwest direction and with 75cm wide. The first sprouting was observed on May 20th. Insects were collected by hand from June 4th on 27 potato and 47 corn plants when both plants were 20cm in height in order to obtain the relative population densities in each plot. Emulsion of malathion was sprayed to clear the population off on July 2nd and 3rd when potato and corn plants attained to 57cm and 50cm in height respectively. After this treatment counts of insects were continued at weekly intervals to compare the faunistic compositions and their seasonal successions with those before the application of insecticides.
In 1957, about 0.1 acre was used under the similar design as in 1956. The field was divided into six equal sections of one twentieth acre, and these sections were used from northern one for potato alone, corn alone, potato alone, potato intercropping with corn, potato alone and potato intercropping with corn. Both potatoes and corns were sown on April 30th in each plot on six ridges in each plot. The first sprout was observed on May 22nd in this year. Insects were collected by hand periodically from June 2nd from the plants on four ridges in each plot. When potato plant attained to 45cm and corn 62cm in height, emulsion of BHC was sprayed on June 18th. After this treatment counts of insects were made at weekly intervals for the same purpose as in 1956. Observations were made twice on July 24th and on August 2nd on temperature, light, solar radiation and wind velocity between ridges at a height of 30cm above the ground-surface in each plot.
The counts made regularly during the entire period of observations of insects in potato fields under different cultural practices are shown in Tables 1 and 2. While both crops remained still low, the first appearance of insect was observed approximately at the same time in both monocrop and intercropped fields, and no significant difference in the increase of insects was found between potato and corn plants. As corn plant grew, however, this difference became significantly apparent in the two years studied, and as can be seen from the following rates

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1. In ordinary paraffin and free-hand sections stained with haematoxylin seven layers may be discriminated in the chorion of the silkworm egg. Superficial two layers, the outermost stained and the next unstained, may be referred to the outer chorion of other authors. The endochorion is made up of five layers. They are from outside a scarcely stained layer provided with many vertical lines which are supposed to be pore canals, a thin laminated layer likewise unstained, a heavily stainable thin layer, an unstained thin layer, and an innermost good stained thin layer (Fig. 1).
2. Methylene blue does not enter into the yolk of the intact egg, but sudan black does readily. The rate of entry of the latter differs somewhat with the varieties of silkworm. Here the thickness of the exochorion is important in slowing down the rate of passage. The activity of the embryo seems also to concern with this. The diapausing eggs show a great resistance to the penetration of the dye, but in the developing eggs such as those under incubation in spring or activated artificially by the treatment with HCl during a few days after being laid it takes place more easily.
3. There is an asymmetrical permeability of acids in the isolated chorion. It is far resistant from without inwards than from within outwards.
4. The penetration of acids through the isolated chorion is enormously accelerated after its innerside has been wiped with chloroform. This does not happen with the outside wiping. There is also no increase in the penetration rate from within outwards by the chloroform treatment. It thus appears that the wax layer which is supposed to be deposited just beneath the endochorion offers the effective barrier to the inward penetration of the liquids, though it has no connection with that in the opposite direction.

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This paper is a part of series of experiments concerning the effect of fertilizers applied to the rice plant on the growth of the rice stem borer larvae. Two kinds of rearing experiments were undertaken to make clear the relation between the phosphorus fertilizer and the growth of borer larvae.
In the first experiment, the larvae were reared in a greenhouse using the rice plants cultured in soil to which different quantities of the phosphorus fertilizer (calcium super phosphate) had been supplied. After rearing for 30 days, it was observed that the growth of the larvae was not affected by supplying phosphorus fertilizer to the rice plant. There were also no remarkable differences on the growth-pattern and chemical compositions in the rice plants cultured with high and low phosphorus levels.
In the second experiment, the larvae were reared with sterilized rice stems (borer zone) in flasks under aseptic conditions as described in the previous papers.
Somewhat better growth of the larvae was introduced by feeding the rice stems cultured in the high phosphorus levels, whereas the difference of larval weights was not significant between high and low phosphorus levels. This result may be due to the high content of nitrogenous compounds found in the rice plant by supplying high level of the phosphate.
From the results of present experiments, it is considered that the application of phosphorus fertilizer on rice plants in an ordinary paddy field has little effect on the growth of the borer larvae

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The soy-bean pod gall midge, Asphondylis sp., has become a very important pest of the soy-bean in Japan, since it was first reported by KANZAWA (1924) in Yamanashi pref. However, life history of the midge has not been well elucidated. This experiment was made as one of the studies on life history of the midge.
During the years 1955, 1956 and 1957, investigations were conducted at Konosu, Saitama. Ten soy bean varieties showing weak resistance to the midge were chosen among the early, medium and late varieties, and were sowed three times. These gave chances of egg deposition to the midges from June to September during the period of adult emergence. Populations of larvae and pupae of the soy-bean pod gall midge and their hymenopterous parasites in inside of the pods were observed periodically at about 5 day intervals.
Occurrence of the midges had a long period from early summer to late autum. A low fluctuation curve of occurrence was found during from the end of June to the middle of August. However, population increased very rapidly in the middle or at the end of August, and reached the highest peak in September of each years. A high population continued from the late August to the early October.
Four species of hymenopterous parasites as natural enemy of the soy-bean pod gall midge were reported; Tetrastichus sayatamabae, Phylomacroploea pleuralis, Pseudocatolaccus sayatamabae and Pseudocatolaccus sayatamabae. These species were found from the larvae of the pests reared at Konosu, Saitama.
Among these parasites the rate of parasitism of P. pleuralis was highest, the avarages being 13.5% in 1956, and 18.1% in 1957. T. sayatamabae followed this, 11.6% in 1956, and 12.3% in 1957. P. sayatamabae and P. tamabae were very rare.
Occurrence of the parasites began at the end of August, and population density was highest in the middle or the end of September.
Types of parasitism were found to be ectoparasitism in P. pleuralis, and endoparasitism in P. sayatamabae and in P. tamabae. But we could not well elucidate the type of parasitism as to T. sayatamabae.

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The Asiatic common looper, Plusia nigrisigna WALKER, is one of the most common species which is harmful to various kinds of vegetables, especially to the cabbage at Fuchu district in Tokyo. It is also found from many prefectures and seems to be widely distributed over Japan.
The author has worked during these several years to clarify its bionomics and physiological natures, the results of which will be published in a series of papers. In the present paper, he wishes to deal with bibliography and nomenclature of this species, as well as to give description of all the stages.
The genus Plusia (sensu latu) OCHSENHEIMER (1816) has been split into many genera by HÜBNER (1821), MCDUNNOUGH (1944), CRUMB (1956) and other workers and the genus Autographa HÜBNER (generotype: gamma L.) has been applied by INOUE & SUGI (1958) to Plusia nigrisigna WALKER. As a result of the author's studies on the larval characters, however, this species seems rather to belong to genus Anagrapha MCDUNNOUGH but not to genus Autographa. The revision of genus Plusia (s.l.) of Japan along these lines is yet almost impossible, for the details of larvae of most Japanese species remain still unknown. Consequently, for the present time, the author prefers to apply genus Plusia (s.l.) to this species.
The genus Phytometra HAWORTH (1809) had already been applied to a group of different subfamily by WESTWOOD in 1840, far before HAMPSON (1913) designated P. festucae as the type of Phytometra. Therefore, the genus Phytometra, though frequently used by many workers, is not applicable to any Plusiine species.
The author has met, in Japan, not a few fragmental reports on injuries by a species called “Plusia (or Phytometra) gamma L.” He suspects, however, that this “P. gamma L.” might be erroneous identification of P. nigrisigna WALKER, for, as far as he has studied, no specimen of Plusia (=Autographa) gamma has been found from Japan, and morever, it is highly possible to confound P. nigrisigna with P. gamma as they closely resemble each other in their morphological features (see Fig. 2: A∼D, and Pl. A∼F) and feeding habits. The comparison between these two species is as follows:
Comparison between Plusia nigrisigna WALKER and P. gamma LINNÉ

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The rice stem maggot, Chlorops oryzae, is one of the serious pests of rice in Japan. It has two generations annually in northern part but completes three generations in southern part of the country. In two-generation area the rice plant is infested only once from the middle of growing stage to heading, and in three-generation area twice in the seedling and heading stages. The symptoms of attack are the injured leaves and ears.
This investigation was designed, first of all, to know the differences in some biological habits of the two regional stocks of the rice stem maggot from two- and three-generation areas, rearing both stocks in comparison under the natural conditions at Ômagari which is in two-generation area. The results obtained in 1958 are summarized as follows:
1. Fly emergence from hibernating grasses peaked about 25 days earlier in the stock from three-generation area than that from two.
2. In the case of infesting normally cultured rice plants, larvae of the stock from two-generation area could not pupate without feeding on young ears, and pupation occurred after the heading period of the host plant which fell on late August. Therefore, the earlier the larvae fed into the plant, the longer their developmental period became. On the other hand, the phenomenon mentioned above was not observed in the larvae of three-generation area.
3. Within 3 months from June to August, stocks from two- and three-generation areas yielded one and two generations respectively on the same host plant. Furthermore, prior to entering into hibernation, an intermediate generation occurred in both stocks were artificially forced to feed on the rice plants cultured in autumn.
4. Injury of leaves caused by larval feeding was classified into four types according to the forms of feeding scars. Some marked differences were observed in the types of injury between two stocks.
5. In crosses between two regional stocks mating was frequently obtained regardless of their combinations, and produced fertile eggs. In F₁ generation, the larval developmental period resembled to that of the stock from two-generation area, but the symptoms of attack were rather different from the cross combinations.
6. Except the intermediate generation, the stock transferred from three-generation area held its original rythm of seasonal cycle noticed in the area of its origin, and seemingly has not been influenced enough by the environmental conditions of the new locality where it was reared. The differences between these two stocks especially in number of generations per year, could not be explained by climatic conditions such as total effective temperature. This may be understood more fully by the supposition of existing biological races and their inherent characteristics which will be maintained through some successive generations of years after transferring to new locality.

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The influences of the concentrations of tissue thromboplastin, CaCl₂ and the stable factor (SF) on the prothrombin time (PT), the plasma thromboplastin time and fibrin quantity in normal plasma, diluted normal plasma (with saline) and warfarin-poisoned plasma or blood have been examined, and the following results were obtained.
1. The concentration of thromboplastin necessary to obtain the minimum value of the PT was 5% in both normal and 40% plasma, and 0.5% in 20% plasma, 10% plasma and warfarin plasma. When the PT was measured by thromboplastin+CaCl₂+test plasma, the suitable concentration of thromboplastin was 10% in both normal and 10% plasma, and 5% in warfarin plasma.
The concentration of CaCl₂ necessary to obtain the minimum value of the PT was 1/40∼1/400M in 40% plasma, 1/40∼1/200M in 20% plasma and 1/40M in 10% plasma. When the PT was measured by thromboplastin+CaCl₂+SF+test plasma, the suitable concentration of CaCl₂ was 1/40∼1/100M in normal plasma, 1/100M in 10% plasma, and 1/40M in warfarin plasma.
2. The concentration of thromboplastin necessary to obtain the minimum value of the plasma thromboplastin time, as measured with thromboplastin+SF+test plasma, was 10% in both normal and warfarin plasma showing the prolonged PT, and 5% in both 10% plasma and warfarin plasma showing the slightly prolonged PT.
3. When the PT was measured with the added SF, the plasma thromboplastin time in normal plasma, 10% plasma, warfarin plasma and the PT in warfarin plasma was prolonged progressively according to the dilution of the SF.
4. When the concentration of either thromboplastin or CaCl₂ was changed keeping the concentration of either CaCl₂ or thromboplastin constant, the PT in warfarin plasma was affected more significantly than those in both normal and diluted plasma by the concentration of CaCl₂ or thromboplastin.
5. Fibrin quantities in normal, diluted and warfarin plasma were affected more significantly by the concentration of CaCl₂ than by that of thromboplastin.
6. The PT of normal plasma was markedly prolonged by high dose of warfarin in vitro. It was found that this is caused by the inhibition of fibrinogen conversion.

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Daily change in the dry weight of the fat body of the silkworm and in its chief constituents was measured during metamorphosis, from the first day of the fifth larval instar to the early pupal stage.
The dry weight of the fat body rapidly increases from the first day of the fifth instar until it attains the maximum value at the end of the spinning stage. After spinning, the weight decreases with age. The female is always superior to the male in the weight of the tissue and this difference becomes more obvious after the ripenning stage.
The change in content of three chief constituents, i.e., lipid, protein and glycogen, was examined. The content of lipid rapidly increases from the initial period of the last larval instar until it reaches the maximum value at the pupation time, and that of glycogen begins to rise from the middle period of this instar and attains the maximum level at the ripenning stage. Protein content rises during the former half period of this instar until it reaches a constant value during the latter half period, followed by a sudden increase in the spinning stage.
As to change in the ratio among three chief constituents, the ratio of lipid and glycogen fluctuates in the same manner and the maximum value of both materials is attained at the ripenning stage. The ratio of protein, however, fluctuates antagonistically as in others, that is, the minimum value is shown at that time. Throughout the development, the ratio of lipid is superior to that of other constituents.
Acknowledgement. Grateful acknowledgement is made to Dr. M. HARIZUKA for his kind help during the experiment and in revising manuscript.

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Nephotettix cincticeps UHLER and N. apicalis MOTSCHULSKY were compared in some morphological and physiological characters and the following results were obtained.
1. In the incubation period of egg, N. cincticeps shows equations, Y=0.0115X-0.165 and y(X-14.3)=87.0 (Y: developmental velocity, y: developmental period, X: temperature), N. apicalis shows Y=0.0102X-0.146 and y(X-14.3)=98.0. These equations mean that N. cincticeps has a higher developmental velocity than N. apicalis, developmental zero point being the same and thermal constant being smaller in the former. The difference is thus in small degree but it persists in the whole range of temperature used.
2. In the larval development too, N. cincticeps has higher developmental velocities in both sexes, though a little irregularity is found at 32.4°C, that is, the velocities deviate from the regression lines downwards in both species and sexes. Regression equations are as follows: N. cincticeps male, Y=0.00496X-0.0664 and y(X-13.4)=201.4; female, Y=0.00456X-0.0601 and y(X-13.2)=219.4; N. apicalis male, Y=0.00480X-0.0647 and y(X-13.5)=208.3; female, Y=0.00440X-0.0582 and y(X-13.2)=227.3. But the differences in developmental velocity are in such a degree that the difference between the two sexes of the same species exceeds that of the two species of the same sexes.
3. In the pre-ovipositional period, no clear difference is found at higher temperature, but the elongation with a fall of temperature is higher in N. apicalis than in N. cincticeps.
4. In the daily rate of oviposition during the first 7 to 10 days after the beginning of oviposition too, no clear difference is found. At 32.4°C the daily rate of oviposition is clearly depressed in both species, probably owing to the harmful effect of high temperature.
5. The body size of adult decreases clearly with a rise of temperature in N. apicalis. On the other hand, in N. cincticeps a slight increase is found in the female, and in the male it decreases but in a lesser degree than in N. apicalis.
6. Sensitivity to photoperiod was studied by the elongation of the larval period and the reduction of the body size of adult resulted under a short day photoperiod of 8hr. As already reported, N. cincticeps shows a diapause in the 4th and/or the 5th larval stage under a short day photoperiod of 8hr at 20°C and adults of the spring form are resulted. In N. apicalis merely residual elongation was observed, accompanying a little reduction of the body size of adult at 20°C and a short day photoperiod of 8hr. The rate of reduction is in a lesser degree than in N. cincticeps.
7. The relation between the two closely allied species which have dissimilar geographical distribution is discussed and N. cincticeps is characterized as a species having a northern distribution area by its higher sensitivity to the short day photoperiod compared with N. apicalis, a southern species.

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[in Japanese]

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An experiment was carried out to investigate the protein and carbohydrate requirements of the rice stem borer larvae during their thirty day period of growth. This period was devided into two fifteen day periods termed as early and late periods. The data obtained showed clearly that the larvae require protein rich food both during early and late stages of their growth and that the high protein requirements are more distinct in the early stages than in the late growth stages. Thus these requirements are different from the European corn borer because in the latter, during its late stages of growth, carbohydrate requirements are greater.

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