Some nematodes are visible with a cheap magnifying glass but not normally the naked eye. You might be seeing baby worms. Have you asked on the worm forum?

There are spring tails and thousands of species of soil mites and I have seen both in my potted plants in the past. Most of these types of critters feed on decaying organic matter but I can't help but think that an over abundance of them could be bad for a plants root system. I would use an insecticidal soap solution and water the plant well with it, should take care of the problem. I will also spray a neem oil solution on the surface of the soil after I water if there are any bugs present. Repotting might be a good idea if the plant has not been doing well and it will give you a chance to take a look at the roots. Mike

i've found this tiny caterpillar on my lilies as well. they eat through the stems just at point where buds start to form. bud group would be cut through and on ground. couldn't figure it out, until i happened upon one of the caterpillars. last year i added bayer dry and liquid grub control to soil when they first started growing. this year i found only 2. i've learned that close inspection is the best way to thwart them. because they're so tiny, they're difficult to find. look for black dots of poop -- a sure sign that something is on them. also if lilies bend away from sun at the start of bud area, check to see if they've been eaten. separate the leaves surrounding buds to see if one is there. do by all means check your other lilies. even if they've been slightly eaten they will bloom.

Ok I have no idea why I can't get a bigger picture up there if anyome knows how to post larger sized pictures let me know