Life history (BugGuide): The female lights on a feeding May beetle, causing it to take flight. Pyrgotid then oviposits into the beetle's back while its soft parts are exposed in flight. The Waved Light Fly usually attack female beetles only and may pursue them under lights. The larvae takes about 14 days to kill the host beetle and then it consumes the entire interior. The fly pupates inside the host remains, emerging the following spring.