Looks like Bay Sucker - if you use your leaves in cooking, and the infestation is extensive, not sure what you can spray with that's okay on edible crops. If its not widespread, pick off affected leaves.

May I ask does it turn into anything else Bamboo?

Not sure what you mean, Drc - the pics above show the first stage, when the eggs are laid, then the bottom pic shows the nymphs hatched out, with their waxy coating. Bay sucker at all stages.

I was hoping they became pretty butterflies or something?

Sorry for late response. Been writing a blog that took over an hour!!
Bay Sucker, Bamboo, That figures, these 2 Bays have had every insect and disease going this year but there still looking good lol. There were 5 leave's and 2 on the other tree infected, there gone now and im keeping an eye on them..ps,I dont use them in cooking and ive sprayed them already.. Thankyou...
Drc, wish they were, I can see how you thought that, The Swelling Does'e looks like a caterpillar, at first i thought they were untill i saw the Nymphs...

:))