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). ライ麦の染色体は長さの順にa, b, c, d, e, f及びgの7種に排列され, それらはまた形態により互に区別点を有することが知られた.
2). 7本の基本染色体はいずれも submedian で, aは時により第二次狭窄をもち, dは時により小形の附随体をもつ. その他の染色体は常に同型で, これらのうちe, fは常に附随体をもち, 前者の附随体は小球形, 後者のは西洋梨型で大きい.
3). aおよびd染色体の変化により, 核型をa₁d₁, a₁d₂, a₂d₁ a₂d₂およびa₃d₂の5型に分つことができる. これらはこの順序に進化して来たものの如く考えられる.
4). 各染色体の形態が明かにされた関係上, 従来論議されて来た異常染色体数をもつたライ麦の起原について, 核形態学的に実証が可能となつた.

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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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