Fluorescent tubes in series?
The lights are gas discharge tubes, so have a struck voltage usually between 60-80 V. So on 110 V mains you won't have enough to keep them alight in series, but at 220-240 V you would have enough voltage. 
If you have a simple inductor/choke limiter, and glow starters this may be your solution:

 

With electronic ballasts it will depend on the connection complexity they support, but there are plenty that support 2, 3 and 4 tubes with heater activation and no starters. Here's a pointer to a 2 tube electronic ballast.