Eleven specimens of Mystacina were available for examination. These are itemized in Table I, in which the abbreviations D.M., A.M., C.M., and V.U.W. are used to indicate Dominion Museum, Auckland Museum, Canterbury Museum and Victoria University of Wellington collections respectively. I would like to thank Dr R. A. Falla, Dr G. Archey and Mr E. G. Turbott for making this material available, and Professor L. R. Richardson for his supervision and guidance throughout the study.