The "jittery" man who tried to hold-up the Bank Of American branch on Acushnet Ave Monday is accused of robbing the Webster Bank on Rockdale Ave in New Bedford on Wednesday.  Police are now looking for 32-year-old John Munoz of Fall River.   On Monday afternoon Munoz appeared jittery when he handed the teller at Bank Of America a note demanding money.  The teller backed off and Munoz fled the bank  without any cash.   On Wednesday, he handed the teller at Webster Bank a note and then took off with the money.   Munoz is also wanted in Fall River for a string of robberies.   New Bedford detectives are asking anyone with information to call 508-991-6300, extension 320.