tiny pale millipedes?

[lobotomizedgoat]

I found these living in the media of my Angraecum longicalcar a while ago. They would emerge and crawl around for a bit shortly after the plant was watered then retreat into the media. I picked off what I saw but they kept coming back. When grabbing them with tweezers there was always a slight crunch like they had an exoskeleton, or something.

When I repotted the plant I felt that there was too much media adhered to and trapped by roots for me to completely remove without damage. At some point when I had mealy bugs in another plant I treated this plant with at least a couple doses of imidacloprid. These bugs didn't appear to be strongly affected by that.

For months now I haven't seen them emerge after watering, but I do still find dead/desiccated remains in the saucer under the pot. The plant itself appears healthy and grows steadily. I've also not seen any evidence of them spreading to my other plants (this one sits somewhat separate from others in my living room).

Does anyone know what they are and what they could be living on?

[for scale that's power+ orchiata and original hydroton (8-16mm), second pic is from phone's macro lens]