Herbarium collections - an invaluable resource for gall midge taxonomists

Dasineura tomentosa is a gall midge inducing distinctive galls on Leptospermum laevigatum. An efficient way of determining the geographic distribution of a gall midge is to examine herbarium specimens for the presence of galls inadvertently collected with the plant specimen. Of the 446 herbarium specimens of L. laevigatum examined 40 had galls caused by D. tomentosa, and two of the three galls examined in detail contained a parasitoid wasp. Despite some limitations, herbarium collections are an invaluable resource for insect taxonomists.