The all-female Tettigoniid grasshopperXiphidiopsis litais a diploid species with 2n=26 (XX+12 pairs of autosomes). There is one pair of huge metacentric chromosomes which, by comparison with the karyotype of the bisexualPhisissp., are interpreted as autosomes. There is no indication of structural heterozygosity in the karyotype ofX. lita, and hence no evidence for a hybrid origin of the species. The cytological mechanism of parthenogenesis (i.e. the nature of the maturation divisions in the oocyte) is still unknown.