Both photos are of the same insect. I took the photos yesterday and only saw one of these insects. I still have a number of other photos of the same insect. The light was hitting at a different angle on the two photos as the insect was moving around quite a bit. I also lightened one of the photos to make it easier to see the color pattern. That was probably unhelpful in this case. Would it help to add another photo?

I've unlinked the photos since it appears from the photos that there were two different beetles on the plant. Those sneaky bugs! Thanks to both of you for your help in IDing them. Think I'll head back to that bush tomorrow and see if there are any others lurking about.

These are definitely two different species, even two different genera! Both are mimics of Hymenoptera, though, and it is enough to confuse almost anyone. Note that Molorchus has abbreviated elytra (wing covers) that expose most of the abdomen and the membraneous pair of wings. The wing covers of the other longhorn are entire.