Figure 45. Monodontomerus wasps lay eggs in the nest chambers of Osmia and Megachile, where their larvae feed on the immature bees. These wasps are tiny and their ovipositors are not very long, but they can easily penetrate paper tubes and other thin-walled nest tunnels (Krunić et al. 2005).
Black bee with red eyes.

Slimguy, Wikimedia