In most Acridoidea the basic karyotype is composed by 11 telocentric chromosomes and a telocentric X (2n=23, X0) in males and 12 telocentric chromosomes in females (2n=24, XX). In this paper we comparatively analyzed meiosis of Z. tarsata (Acrididae, Romaleinae) and P. acuminata (Pauliniidae) after C-banding and DAPI staining in order to investigate differences due to heterochromatin amount and localization. Z. tarsata and P. acuminata showed a karyotype composed by 11 somatic telocentric chromosomes and a telocentric X, corresponding to 2n=23, X0 diploid karyotype in males. After C-banding procedure Z. tarsata pachytene bivalents showed 12 densely stained spots including the X chromosome, 4 of these were observed in interstitial locations and the remaining in pericentric position of the telocentric bivalents. In P. acuminata 4 C-banded spots were observed, 2 of these in interstitial locations and the remaining in pericentric position. After pachytene DAPI staining, bivalents showed specific bright stained areas corresponding to those detected after C-banding in Z. tarsata, the same was observed in P. acuminata. These differences demonstrate that despite chromosome similarity between these taxa heterochromatin evolution seems to follow a different path, allowing a clear differentiation between these two karyotypes
