Nineteen metaphase cells stained for the structural heterochromatin (C-banding) were analyzed. The clearly stained pericentromeric heterochromatic blocks, which sizes were approximately the same, were identified at all chromosomes of Ochotona huangensis. The heteromorphism was detected by localization of heterochromatic blocks on the 8-th pair of autosomes. An intercalary heterochromatic block was always detected in the long arm of one homologue of the 8-th pair. Also, that homologue had the pericentromeric block of heterochromatin. In the second homologue of this pair, the intercalary heterochromatic block was detected in nine metaphase cells. In the remaining cells, only the larger pericentromeric heterochromatic block was detected in this homologue. By that, the euchromatic site, which separates the intercalary heterochromatic block, was broader on the first homologue than that on the second homologue (Fig. 4). We can’t characterize this phenomenon in details and discuss about its nature, because of the absence of sufficient material. So we leave it only as an observed fact. The X chromosome has a pericentromeric block of heterochromatin. The heterochromatic region occupies 2/3 of the lower arm on the Y chromosome