I would be afraid that it might be the eggs of a canna leaf roller...I personally don't know what they look like, but that is the only critter I can think of that would be laying eggs on canna. You don't want those.
Do you have aphids on the canna? Ladybugs don't lay their football shaped eggs on bare plants. They have to have food for their larvae when they hatch.
You could always take a section of the leaf and put it in a jar and see what hatches. Canna leaf roller and lady bug larvae look nothing alike. If it turned out to be ladybug larvae, you could always return them to the plant. And if it turned out to be canna leaf rollers, you could flush them.