Ah BenB can likely give a more precise answer on that, but I think those are just like temp Auto Saves or something. I've had them show a few times in my trash as well (only sometimes though, not consistently). I've trashed them and never had a project not work or go corrupt or anything like that. I think you'd be safe. Again, maybe wait for BenB to chime in on this one though, he might be able to give a more technical answer as to what those files specifically are.
Those are the old Auto Saves. For example, I have mine set to save every 10 minutes, the last 6 versions of those saves, for the last 5 projects I've worked on.
So, every 10 minutes it writes an FCP project file (Save As) to the hard drive. When it does this for the 7th time, it takes the oldest version and moves it to the trash.
This way, if anything goes wrong (with my computer, or my brain), I have versions that span the last hour of work I did. Very cool feature!
What you see are older, discarded copies of the Auto Save backups. Trash them. Then go into your Auto Save settings (User Prefs) and think about what sort of saftey net you want to set it up to give you.
It's a super cool feature that has saved my butt (as cute as it may in fact be) on many occations that would have been nightmares without the Auto Save.