Although I confidently say they are raids in the title, let's see the evidence:
First, I came across this harvester ant nest with dead ants, about half of which are light-colored callows. No live ants to be seen.
A nearby entrance hole had a lot more activity. The workers are actively grabbing each other.
By the way, the seed was going out, not in.
From out of the nest came workers carrying callows.
Here's another one.
Up out of the nest...
... and off it goes.
This one is carrying a worker.
After a short while, the excitement died down a bit.
When Pogonomyrmex raid weaker colonies they are known to carry off larvae and pupae. I didn't see any of that, but I couldn't watch that long, either. We were at a park and kids were playing.
What do you think? Was it a raid?
In another note, James asked about the color of the silverfish.
It appears to be creamy-silvery in color. It didn't stay outside for long though. It zipped out and zipped back in. The quality of the photograph leaves a tad bit to be desired.