The chromosome formula, n <5 = 13 (X. hi), characterises 4 spp.: Austrolestes colensonis (White) (Lestidae), Uropetala carovei (White) (Petaluridae), Procordulia grayi (Sel.) and P. smithii (White) (Corduliidae). The karyotype of Xanthomemis zelandica (McLach.) (Coenagrionidae) is described by n <J= 14 (X). Save for U. carovei none of these spp. have been examined cytologically so far.