The chromosomes of two species of the Cicadidae and six species of the Cercopidae were studied in this investigation, with special regard to the morphology of the chromosomes and to the sex chromosomes.
The chromosomes of the Homoptera morphologically belong to the “Chromosoma pleuromiticum” after the nomenclature of Oguma (1942). The chromosomes arrange themselves on the metaphase plate in a circular manner which is usual throughout both. the Heteroptera and Homoptera. The sex chromosome is an X-O type in the Cicadidae, while in the Cercopidae the majority of species show an X-Y type.
The species herein studied and their chromosome numbers together with the sex chrosomes are listed in the appended table (Table 1).

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Auramin which was dissolved in Ringer-Locke-Barta's solution at concentration of 0.01%, was injected in the abdomen of the grasshopper (Podisma sapporense), 0.02cc in each. After 30 minutes, the course of division was followed in living spermatocytes by the hanging-drop method, with the aid of a phase-contrast microscope.
By application of auramin the cells tend to fuse with one another into giant cells and this leads to the formation of the multinucleate cell. In this present study, the process of the formation of the multinucleate cells was successively traced in a single cell.
Evidence was presented to show that the mitochondria plays an important role in the division of the cell body.

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The chromosomes of eight forms of the Chilopoda were comparatively investigated in this study, especially with reference to the relationship of the cytological characters upon taxonomy. The taxonomic arrangement of the studied species and their chromosome numbers here established are shown in Table 1.
The chromosomal relationship between Scolopendra subspinipes mutilans and S. s_??_ japonica was interpreted on the basis of both the morphology and the number of the chromosomes.
Though Otocryptopus rubiginosus and O. sp. are closely related belonging to the same genus, the chromosomes of these two species failed to show any morphological kinship.
The chromosomes of Bothropolys asperatus and Esastigmatobius longtitarsis belonging to the Lithobiomorpha showed a remarkable difference not only in the number of chromosomes but also in other morphological features.
Thereuonema hilgendorfi and Thereuopoda clunifera were proved to show similar chromosomal feature, being characterized by having the XY-XX sex-chromosome mechanism.

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1. In this investigation external characters and maturation division in P.M.C-s of back crossed hybrids raised from Haynaldia villosa×Secale cereale F₁ with S. cereale were studied cytologically.
2. 12 individuals of back crossed hybrids were raised by crossing 2073 flower of H. villosa×S. cereale F₁ plants with the pollen of S. cereale, the percentage of which is 0.58%.
3. The back crossed F₁ plants resembles morphologically rather to rye than the H. villosa ×S. cereale F₁ plants (Fig. 3 and Table 1).
4. The number of chromosomes of the back crossed F₁ plants was 2n=21 and 20. In either of these numbers, 7 chromosomes seem to have come from S. cereale and the remaining 13-14 chromosomes from H. villosa×S. cereale F₁ as the mother plant.
5. The number of bivalents in one P.M.C. at 1st maturation division was 1-8 in the case of having 2n=20 chromosomes. But in the case of those having 2n=20 chromosomes, the number of bivalents has voried 1-7 or 0-8 according to individuals (Table 2 and 4). Those bivalents of the former case i.e., of the individuals having 2n=21 chromosomes, appears to result from autosyndesis between the chromocomes of R genom of S. cereale and between those of V genom of H. villose respectively. And in the latter case of those individuals having 2n=20, in addition to the bivalents due to autosyndesis, a bivalent resulting from allosyndesis between chromosomes R and V genoms seems to exist, though very rare.
Some of these bivalents were observed as the univalents resulting from early splitting. Trivalents and tetravalents, in addition to the bivalents, were observed in rare cases.
6. From the result obtained in the study on the maturation division in P.M.C-s, the constitution of genoms of these back crossed hybrid F₁ plants seems to be VRR in the plants having 2n=21 chromosomes and VRR-1 in that having 2n=20 chromosomes.
7. The chromosomes were distributed to the poles at ana-telophase in 1st maturation division is almost equal numbers.
8. The back crossed F₁ plants were completely sterile in male and female gametes.
9. As abnormal cases of P.M.C-s in maturation division, the giant P.M.C-s having 30 or more nuclei (or having chromosomes corresponding to the numbers of nuclei) were observed frequently in these back crossed F₁ plants. These giant P.M.C-s seem to have resulted from repeated nuclear divisions without cell divisions.

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1) Karyomorphological study was made on somatic chromosomes of Secale cereale L., and it was found that seven pairs of the chromosomes were distinguished each from others in their length and shape.
2) In this paper these chromosomes were designated as a, b, c, d, e, f and g, accordingly their length were all characterized by the respective morphological features (Figs. 1, 2).
3) Though all of the chromosomes are of submedian type, the “a” chromosome in a certain varieties has a secondary contriction in the long arm, and the “d” of some varieties has a small satellite attached to the end of the short arm. The other chromosomes, however, show no different figure in any variety. A satellite is always observed in the “e” and “f” chromosomes, but that of the “e” is sphaerical and smaller than the pyriformic satellite of the “f”.
4) As three different types are found regarding the “a” and two types in the “d”, five karyotypes are distinguishable in rye plants, e.g. a₁d₁, a₁d₂, a₂d₁, a₂d₂ and a₃d₂(Fig. 3).
5) In the first type, a₁d₁, the characteristics of each pair of the chromosomes are as follows:
a……about 10μ long, of submedian type without secondary constriction,
b, c and d……submedian type,
e……submedian type with a small satellite on its short arm,
f……submedian type with a large satellite on its short arm,
g……about 6μ long with submedian constriction.
This karyotype was observed in a race, “Greenland Original”.
6) The second a₁d₂ type, is characterized by the “d” chromosome having small satellite on its short arm, though remaining chromosomes are similar to the first type. This type was found in “Deve de Sarve” and a certain race of spring rye.
7) The third type or a₂d₁, shows characteristic constrications in the long arm of the “a” chromosome, and has “d” chromosome similar to the first type. “Korean” No. 1 and No. 2 are of this type.
8) The fourth a₂d₂ type, which is almost similar to the former a₂d₁, type, is distinguished from the a₂d₁, by the peculiar “d” with a small satellite on its short arm. This was found in the varieties, “Podolia” and “Trisperuum”.
9) In the fifth or a₃d₂ type is found curiously shaped “a” chromosome: this has two secondary constrictions in both arms near the spindle fiber attachment, and looks like as if two tadpoles are connected with their heads each other. This was a type found in “Petkuser”.
10) Among those types listed above, the a₁d₁, seems to be the most primitive one and types of a₁d₂, a₂d₁ a₂d₂ and a₃d₂ may have changed gradually in chromosome morphology from the type of a₁d₁.
11) It was suggested that this study will faciltate to solve the pending problem concerning the origin of extra chromosomes found in 8-, 9- and 10- chromosome rye plants.

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Regarding the amylase activity of Bomhyx mori, there are four genetical strains, +^ae, +^be, ae and be. Comparative studies of the amylase action of these strains were carried out by means of the sugar-measurement and the iodine-starch reaction. The results show that the “amylase free strains”, ae and be, are not completely free from amylase but they show the enzymic activity, though very weak, in the later larval stage and also in the pupal stage. According to Matsumura and Kikkawa, there are various grades of amylase activity in +^ae and +^be. From these facts, it may be supposed that the amylase activity in digestive and body fluid would cover a wide range of degree from + to -. Furthermore, as reported by Matsumura et al., amylase activity in the silkworm is influenced by various factors, such as rearing conditions and the developmental stages. The genetical phenomena of the amylase action in the silkworm seem to be very complicated.

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