I am trying to identify this bug that has been present in my bathroom for maybe 6 months. It is on average about 2.5 mm long and .5 mm wide, and it can crawl surprisingly fast when moving. The picture makes the bug appear to have approx 8 sets of legs or maybe a body of 8 segments and some sort of pincers or antennae at the head. At the other end it is silver colored; I can't tell what the silver is, or if it is a trick of my camera. Most often I find it on the tile above the tub at the opposite end from the drain, but I also find them in the tub and one time one or two on the bathroom ceiling.  I don't have a camera that will take finer pictures than what my phone will do. I am not fully convinced that the bug comes out of the bathtub drain, as is commonly thought; Sometimes I suspect that it is coming out of cracks in the caulking at the top edge of the tub where it meets tile or through crevices in the bathroom window. 

The primary appearance of the organism to the naked eye is black, and the shape is roughly straight on both sides.

In the past I have seen some silk-like strands high up on the bathroom walls or ceiling. I do not know if the bug in question is causing them.

I did use an enzyme drain cleaner for a few months and I had thought that this had fixed the problem, but then they came back. I would say that I find 2 or 3 in a day, but sometimes none.

Another source just suggested that this is the bristly millipede, Polyxenus lagurus. If this is accurate, where do they hide, how do they get inside, what is best way to eradicate? Could they be hiding behind bathroom tiles? Getting in through the window from the outside?