Chalcis canadensis
Parasitizing Soldier Fly Eggs

Chalcis canadensis (Cresson) parasitizing soldier fly eggs (Diptera: Stratiomyidae). This standing method of oviposition, often employed by this species, allows the female to free an egg from the mass, swing her abdomen forward to oviposit into the egg, release the egg and swing her abdomen (with egg still on ovipositor) behind her where the egg is deposited into a growing pile of parasitized eggs.

References:

Cowan, D. P. 1978. The function of enlarged hind legs in oviposition and aggression by Chalcis canadensis (Hymenoptera: Chalcididae). Great Lakes Entomologist 12(3): 133-136.