【摘要】 <正> 引言 Roberts(1941)根据外生殖器形态的不同,将蝗科(Acrididae)分为两大类:即Chasmosacci和Cryptosacci;前者包括癞蝗亚科(Pamphaginae)和锥头蝗亚科(Pyrgomor-phinae),后者包括所有其他蝗亚科。细胞学研究指出,癞蝗亚科(Granata,1910;Ch’en,1937)和锥头蝗亚科(McClung,1932;Rao,1937;Sharman,1952)的染色体数目与其他蝗亚科有所不同。White(1951)总结为:癞蝗亚科和锥头蝗亚科的染色体基数为2n=19;而其他蝗亚科则为2n=23。但到目前为止,特别关于癞蝗亚科的染色体研究已发表的只有Pamphagus marmoratus Burm.(Granata,1910)和笨蝗Haplotropis更多还原

【Abstract】 The chromosomes of Pseudotmethis alashanicus B.-Bicnko, belonging to Pamphaglnac of the orthoptcran family Acndidae, have been studied. There are nineteen acrocentric rod-shaped chromosomes in the spermatogonial cells. This finding confirms the observations of the previous investigators that the basic chromosome number of Pamphaginac grasshoppers is 2n cf = 19. However, an abnormal secondary spcrmatocytc with nineteen chromosomes (2n) has been found and it is postulated that the polyploid spcrma-tocyte may possibly arise from a failure of cytokinesis at the first meiotic division.Upon the study of the morphology and behaviour of the chromosomes of Pseii-dolmethis, it is found that the smallest pair of chromosomes are of an oval shape and further that the large X chromosome of the spermatogonial cells as well as the large double cross bivalents of the first spermatocytc are very much like those described by one of the present authors (Ch’en) for Haplotropu. The double cross element of both Pseudotmethis and Haplutropis is characterized by large and deep stainability of its chromomcres with an indication of precocity of behaviour, and its movement is more restricted than that of the other autosomcs during the meiotic prophase. It is, therefore, suggested that there is a definite intergeneric chromosomal homology between Psen-dotmethis and Haplotropis.更多还原