We have seen at least five species of this Genus in the park, four of which look the same except for the size and the relative length of the ovipositor (the needle at the back). The one above has the shortest ovipositor. Another species has an ovipositor about two thirds the length of the abdomen, the third species (which is small) has an ovipositor longer than the body, and the fourth species has an ovipositor about twice the length of the body.
Classification
from Australian Faunal Directory
Order Hymenoptera - Wasps, Ants, Bees and Sawflies, 12202 named species in Australia
Family Gasteruptiidae - 190 species in Australia
subfamily Gasteruptiinae
Genus Gasteruption - 114 species in Australia
Species ?