Although nearly 1,500 species of Heteroptera have been studied cytologically, there are only about a dozen putative cases of polyploid species. Thus polyploidy has not generally been a significant mode of speciation in the Heteroptera. A case can be made that the ancestral autosome number for each of the 7 infraorders of the Heteroptera is 20. That is, 10 linkage groups appears to be the ancient genomic organization for the suborder, and this is conserved. None of the infraorders evolved by an increase, polyploid or otherwise, of the basic chromosome number. One of the most successful groups of Heteroptera, the Trichophora, appears to have originated with a massive fusion of the autosomes, which reduced the number of linkage groups from 10 to 5. A number of genera (Halobates, Lopidea, Naucoris), tribes (Cymini, Petascelidini), and subfamilies (Scaptocorinae) can be identified that may have had a polyploid as the most recent ancestor. The case can even be made that Gelastocoridae and Miridae, the latter certainly one of the most successful families of the Heteroptera, originated as polyploids.