Abstract
Hemideina trewicki, a new species of Stenopelmatidae from Hawkes Bay, is described. Morphologically it differs from H. crassidens only in the colouration of the pronotum but it can be distinguished using two allozyme loci (Ldh-2 and Pgm-1) and the number and gross morphology of the chromosomes. H. trewicki can be sympatric with H. thoracica and although a (probably sterile) F1 hybrid has been found, these two species have four fixed allozyme differences and karyotypes which clearly distinguish them.