Black Worms with Big Heads in Bath are Drain Fly Larvae

"I was taking a bath when I saw two small worms in it with me", writes Pam in her submission about the tiny, black worm-like creatures pictured below. "I want to make sure that they are not harmful. They had larger “heads” and thinner yellow and black tails. I have never seen them before." To start with, we want to thank Pam for the excellent photos she sent us: the resolution is so good that we can even see the finest details on these critters when zooming in on the photos. And it was because of this that we managed to come to a conclusion regarding their identity. Well, sort of.