This mining bee was in my office today and look what was peaking out of its abdomen - a female strepsipteran (probably a Stylops sp.). Naturally, I had to dissect it. More pics in the thread.

Look out for these now in some solitary bees, especially Andrena scotica.

Carefully remove the tergites and you can see the parasite in situ. Only the dark brown portion (cephalothorax) protrudes from the host - it's become a bit detached here. The rest of her body is in the host's abdomen.

This is the entire parasite extracted from the bee's abdomen and laid alongside, so you can how big it is. Sometimes, there can be several of these in the host.