Note the elongated head. I found this thrips when I opened a Solidago canadensis stem to check on successful/failed emergence of nymphs from last season's tree crickets eggs. I've opened hundreds of old stems over the past few years, and have found a lot of dead fully developed parasitoid wasps (Oethecoctonus oecanthi) that never emerged, but this is the first time I've found a thrips -- and it was still living. I did find several mites inside the stem, and I presume the thrips was eating on thrips eggs.

I thought perhaps that the elongated head would make this an easy ID, but apparently not. I have found several other photos of similar looking thrips, but they have never been ID'd to species.

My guess would be Leptothrips mali, because I did find a matching photo on another site, but they indicated the length of Leptothrips mali as 1.8mm. Mine measured 3mm.

there are lots of photos of thrips similar to mine.Here are some of the other photos: