Ichneumonoidean wasps are important parasites of other insects. Common hosts are larvae and pupae of Coleoptera, Hymenoptera, and Lepidoptera. There are approximately 3,000 species in North America - more than any other Hymenoptera family.  One way they differ from the wasps that sting (Scolioidea, Vespoidea and Sphecoidea) is that the antennae are longer, usually with 16 or more segments. Female ichneumons frequently exhibit an ovipositor longer than their body. Ovipositors and stingers are analogous structures; some Ichneumons inject venom along with the egg, but they do not use the ovipositor as a stinger per se. Stingers are used exclusively for defense; they cannot be used as egg-laying equipment. Males wasps do not have stingers or ovipositors. In some species of Ichneumon wasps, both sexes will wander over the surface of logs, tree trunks, and even grass stems tapping with their antennae. Each sex does so for a different reason; females are 'listening' for host larvae upon which to lay eggs, males are listening for newly emerging virgin females with which to mate.  Upon sensing the vibrations emitted by such insect larvae, the female wasp will drill her ovipositor into the substrate until it reaches the cavity wherein lies the larva. She then injects an egg through the hollow tube into the poor unfortunate's home (sometimes inside the larva itself). There the egg will hatch and the resulting larva will devour its host before emergence. If you happen across one at work, approach slowly and carefully. You're in for a treat watching this fascinating process. You can view a series of large closeup pictures and a video of the giant ichneumon wasp Megarhyssa drilling and laying her eggs HERE.

Family Braconidae - subfamily Aphidiinae. Tiny braconid wasp (3mm) lays eggs on aphids. Shown with milkweed, Asclepias sp.

I very often see small Ichneumon females hunting amidst low foliage. They are maddeningly difficult to track, their movements are so frenetic. They fly rapidly from plant to plant, sometimes stopping to explore one of the leaves in detail, and this is when a photographer must be ready to quickly approach and take the shots as quickly as possible. (Good practice for any insect photograph, I guess).  Many of the pictures here were taken with a couple old Kodak point-and-shoot cameras - that made it much easier becuse all I had to get close to the subject was my hand holding a camera, and not my head and face and huge lens, like I do now (with a DSLR).

This female wasp is about 4 inches long. Xorides sp.

This female wasp is fully 4 inches long, including ovipositor. Megarhyssa

Video of the egg-laying process.

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