Chromosome banding techniques have been used in a large-scale survey of karyo- typic variation within and between the chromosomal races of the Gehyra variegata-punctata species group. A total of nine chromosome races are now known among these taxa. G-banding confirms that the principal mode of chromosome change is centric fusion and, in most cases, allowed the specific chromosomes involved to be identified. The location of C-band heterochromatin and the nucleolar organizing region varied within and between the races. In two of the chromosomne forms, heteromorphic sex chromosomes were observed in the early stages of evolution. The cytogenetic characters were evaluated and then used to construct a phylogeny for these taxa. The types of chromosome change between the races and their geographic relationships were then considered to examine the role of chromosomal mechanisms of speciation in these gekkos. The previously suggested role of single centric fusions as initiators of speciation in Gehyra requires further evaluation. In one case, an unusual form of tandem fusion has been established and this race is clearly reproductively isolated from all others. The presence of monobrachial homology between the biarmed chromosomes of some taxa suggests that a distinct mode of chromosomal speciation may also be important in Gehyra. (Chromosome evolution; speciation; cytogenetics; Gehyra.)