Uresiphita polygonalis maorialis (the kowhai moth) is a well-known defoliator of Sophora spp. plants in New Zealand. Here data is presented from an experiment carried out between December 2007 and February 2008. The relationship between densities of U. polygonalis maorialis and the emergence rates of the parasitoid Meteorus pulchricornis were studied. Results show a positive correlation (r = 0.51, P<0.01) between densities of U. polygonalis maorialis and the emergence rates of adult M. pulchricornis. Emergence rates recorded through the studied months were 5.8% in December (n = 68), 28.5% in January (n = 70) and 16.4% in February (n = 67). These findings could be explored in detail in order to clarify the mechanisms driving host-parasitoid interactions and the relationship between emergence rates of M. pulchricornis and larval densities of U. polygonalis maorialis.