Photo by Drees. Photo by Drees. Adults of Megarhyssa macrurus lunator have brown bodies, up to 1 in length, marked with black and yellow markings and transparent wings. Adults can sting and are frequently encountered around lights in and around the home.
Most ichneumons are smaller parasitic wasps.
Most species overwinter in the cocoon as a mature larva, although some spend the winter as adult females. There may be one to 10 generations produced annually depending on the species. The larva of M. m. lunator hatch from eggs inserted into the tunnels of the pigeon tremex. Adults emerge in the spring. Mouthparts are for chewing.