In 2 d final instar larvae from Lake Sarah, South Island, New Zealand, the chromosome complement was counted as 2 n = 25, n = 13 (X, m). The material originates from the same locality as that studied by L.S. WOLFE (1953, Trans. R. Soc. N.Z. 80: 245-275), who reported 17 elements in the diploid set. A re-examination of the latter’s figures suggests that the count was erroneous.