| In this paper, the model karyotypes of Monochamus alternatus Hope, Anoplophora glabripennis Motschulsky and Apriona germari Hope were studied. The experimental materials were the different tissues and organs which were dissected from larvaes, pupaes, adults and embryos. Conventional squashing method was used to make specimen of chromosomes by changing some conditions, such as dose of colchicine, time of hypotonic treatment and frequency of Carnoy fixed. The results were observed to ascertain the best experimental material and condition. BSG(Barium hydroxide/ Saline/ Giemsa)was adopted to make C-banding with pH 6.8 Giemsa (5%). C-banding of the three species were observed repectively.The main results were as follows: The best material for Monochamus alternatus Hope was spermaries or ovaries of 7-day-old pupae. The chromosome number was 2n = 20. The sex-determining mechanism was Xyp . The genome-style was 5 L + 4 M + Xyp; The best material for Anoplophora glabripennis was spermaries or ovaries of the beginning of adult eclosion, and its haploid chromosome number was n = 10, Sex-determining mechanism was Xyp, Genome-style was 6L +3 M + Xyp. To Apriona germari Hope, the best material was 2, 3-day-old embryos. The chromosome number was 2n = 20, The sex-determining mechanism was XY, The genome-style was 5 L+ 4 M + XY; The nucleic acid content of Apriona germari embryo was determined by using spectrophotometry method. The content was growing with age increasing, and 3,6,9-day-old embryos appeared peak value. The ratio of RNA/DNA of 3-day-old embryo was higher than 6,9-day-old embryos, this result was consistent with the best material choosing of Apriona germari embryos. C-banding patterns of the three species were studied by C-banding technique, but the patterns were obscure. It showed that chromosome of Monochamus alternatus had banding lines, most were circular or oval. C-banding patterns of another two species were hard to observe.
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