We just installed a new bathtub and as I was about to fill it up, I stopped when I saw a rather large bug inside. It looked like a silverfish, but it was significantly larger, 3/4 or an inch long. And it wasn't silver. And it jumped when I tried to catch it. I took a couple of photos before we relocated it out into the backyard, where bugs belong.
I looked for information on the internet and learned that it is a bristletail, or a jumping bristletail, maybe a Trigoniophthalmus alternatus, or an Mesomachilis. These normally live outdoors in the detritus of trees and shrubs, and feed on lichens and moss. So how did it get in our tub? Good question, no answer.
These bristletails are one of the most primitive of all insects. The oldest insect fossil found to date looks a lot like a silverfish or bristletail. They do not have wings and never did, evolutionarily speaking, which is unusual for insects.