I had some of these last year and dumped the tray out to get rid of them. This year I thought I'd try to figure out what they are. They definitely don't look like mosquito larvae and seem too thin and long to be fungus gnats. They just appeared suddenly over the past week and wiggle around on the bottom of the trays. It's hard to get a measurement when they move so much but I would estimate they range from 3-8mm long. Any ideas?