You could have Thrips of course, it's just not usual for them to bother non flowering plants. The most common Thrips (it's always plural) is the Western Flower Thrips and they feed mainly on flowers. They are somewhat as you describe them, but they are slender, about the width of a human hair. There is another type of Thrips that has invaded the lower south called a Chili Thrips. They will feed on the leaves as well as the flowers. They are a real menace, but are not too common outside of the deep south - yet. Thrips do lay eggs in the soil, but I've never caught them emerging and don't have a clue what their pupae to adult life cycle looks like....I would definitely keep this plant in quarantine. I'm just curious how all these bugs got inside an office building? Is this a new plant you just brought inside?......... If the outbreak gets serious enough with more mystery bugs showing up, by all means repot the plant taking care to wash off all the old soil and using a new well drained potting mix. Wash off the leaves as well in case there are any eggs laid on them......Hope this helps.....Maryl

Thank you, Maryl! I've had this plant for a few months, but recently brought it to the office (I recently moved didn't have room for it in my apartment). There's a large pile of mulch outside my window which attracts a lot of insects for some reason - perhaps that could be the origin?

Mulch has many blessings but it also has a few problems. It is a great place for slugs, rolly pollies, crickets, spider mites etc. to hide. Window Screens usually keep most things out if your window is up, but it's not always the case perhaps. Really small insects like Thrips might be small enough to pass through a screen once in a blue moon. I've dropped things down into the space between my kitchen cabinet and my refridgerator that I could have sworn would never have fit......Whatever happened, or whatever the bugs are, I hope you get a handle on it and eliminate the pest. Repotting into new potting mix would be a good start.........Good Luck.......Maryl

It is close to impossible to identify a pest without a photo. They might not even be pests. Many bugs that live in or around our plants and soil aren't harmful at all. A photo of the critters would make all the difference in the world.

I'm guessing your Sans is probably too damp, but again, I can't know without some photos. I suspect it because you mentioned critters in the drain dish rather than on the plant or soil surface. Often, bugs are attracted to the drain dish because the soil in the bottom of the pot is wet and rotting. Lots of bugs feed on detritus, and damp, decaying soil or mulch is very attractive to them. Theyd move right over from the mulch like. Are you sure your bugs can't fly? Fungus gnats will often scurry rather than fly. They're harmless to plants, but attracted to wet soil.

Anyway, if you can get some photos of the bugs and your soil, we're a lot more likely to be able to positively identify your critters. I agree that thrips aren't very likely on a non-flowering plant, and especially unlikely on a leaf as tough as that of a Sans.