probably caterpillars
they love cannas

Are there any droppings anywhere?

I second caterpillars.
One of the photos shows the edge of a leaf rolled back.
Pull back that section of leaf and I'll bet you find one of the culprits there.

Droppings? I've looking @them several times a day picking through the leaves haven't seen any caterpillars. Are they goners. Or is there something I can treat them with? Thx.

If you Google "Canna Leaf Rollers" you can find out about this pest. BT is a control specifically for caterpillars but you have to use it often to keep them off. I have the same problem. There is also a disease that affects Cannas, I love them but it's a constant battle to keep them healthy. I have used Sevin dust for them and it works but also have to reapply often to get good results.

Grasshopper/Lubbers love cannas too.

Droppings or poop. Many times the bug is gone but what he leaves you with, poop, can id who it is. I would douse with Seven. Look down in the soil too. Many times cut worms are sleeping there during the day. Good luck.

I spy a rolled up leaf edge in the last pic, you might want to pry that open & check what's inside.

The good thing about those caterpillars is that they don't stick around for long - it's only for a short time & then they pupate.

I get rust alot and then they look half dead. When they do that I just cut them to the ground, they look awful anyway and let them grow back. They usually come back healthy and blooming. :o)

I was also thinking landlubber grasshoppers. They have an incredible appetite. I don't think they leave frass (poop).

I learn something new here every day, like insect poop is frass. Thanks Zackery! :o)