Ichneumon wasp species are highly varied, ranging from to long. Most are slender, with the females of many species (particularly in the genus "Megarhyssa") having an extremely long ovipositor for laying eggs. The female finds a host and lays an egg on, near, or inside the host's body. Upon hatching, the larval ichneumon feeds either externally or internally, killing the host when they themselves are ready to pupate. Despite looking formidable, the ovipositor does not deliver a sting like many wasps or bees. It can be used by the wasps to bore through rotten wood, and lay eggs in grubs hiding under the wood.