This is one that I find a little surprising, in that it’s only appeared once here, and probably not a whole lot more often in my stock either. This is a six-spotted tiger beetle (Cicindela sexguttata,) and they’re not only fairly common, they’re obviously quite easy to spot – chances are, if you live in most of the eastern US and spot something bright iridescent green, it’s one of these guys. Granted, they’re hyperactive and spooky, rarely letting a close approach happen, and I do recall that I had to crawl up to this one carefully to get this portrait with the macro lens, and even then considered myself lucky to have pulled it off. But this was also just shy of nine years ago, and I would have thought I’d have the opportunity to snag more in that intervening time, but here we are.
I would also think that the bright coloration is a ‘keepaway’ signal, something memorable that goes along with a nasty defensive mechanism so birds and other predators create quick associative memories after an encounter: “Okay, that wasn’t fun! Note to self: avoid the shiny green ones,” Except that I find no mention of defensive traits, so either those jaws are even more capable than they appear, or there’s another purpose to being so easy to spot. I will also note that their style of movement is not unlike some species of wasps: agile and quick to fly, but also kind-of stop-and-go movements on the ground, and a lot of predators recognize prey and not-prey more by their behavior than appearance.
While some indication of size might be determined by the short depth-of-field here (meaning high magnification,) I can simply tell you that the species runs 10-15mm in body length, which seems about right to my memory – I didn’t get any measurements at the time, and I’m quite sure that it wouldn’t have stood happily for me sliding a paper ruler into the frame.