ヒナバッタの減数分裂前期染色体の細胞学的研究

The meiotic chromosomes of Chorthippus bicolor were studied from squashed preparations of testicular follicles. Seventeen chromosomes were karyotypically analysed in spermatogonial cells. In the course of observations with spermatocytes in early prophase an interesting feature of a partial heterochromatic bivalent has been seen. This characteristic feature on a bivalent constantly appeared through early prophase, from zygotene to diplotene stages. From the pachytene karyogram, the bivalent was identified as the telocentric element of No. 6. The condensed segment localized on one distal thirds of the No. 6 bivalent and the chromosome tended to associate with heterochromatic X element through prophase stages. The significance of the peculiar type of bivalent has not been defined yet.