This was along Mill Creek outside of Walla Walla, Washington a couple weeks ago. There were a lot of meadowhawks (Sympetrum) around—mostly Band-winged Meadowhawk (S. semicinctum) and Striped Meadowhawk (S. pallipes), soaking up a little afternoon sun when the clouds parted. We found this good-sized, plump mantid just off the trail with some Band-winged Meadowhawk remains nearby. I have to assume that the mantid caught and devoured the meadowhawk (its head and thorax, anyway, leaving the wings and abdomen as scraps), and perhaps it was waiting to ambush more that landed within reach of its raptorial forelegs.
The mantid isn’t the native Litaneutria minor, which is a small species (no more than about 1.5 inches in length—this one was about 4 inches) and finely patterned with speckles. I presume it is one of the non-natives, but I couldn’t tell you which one. I wonder if it’s a gravid female with that very plump abdomen—or else she is just full of Sympetrum.
The mantid standing up next to that leaft makes it look like she’s at a dinner table waiting for the next course. She also looks like she is going to pick her teeth with that piece of straw in her forelegs. Wait... ...now that I look at it very closely, I can see that it’s actually an insect tarsus—probably from a mantid. I don’t see her right rear leg, so maybe it’s hers? Maybe it came off in the struggle with the meadowhawk or she tangled with another mantid. I don’t know.
Here’s another view, so technically this isn’t just “a” photo...
This appears to be a European Mantis, Mantis religiosa. Thanks to those who commented.