Well, you're not really minimizing power dissipation here with the pre-regulator.
Your pre-regulator is a very simple linear regulator that is designed to provide a lower input voltage to your LM317 regulator. The Zener diode and R3 will provide a relatively stable 14 V. Transistor Q1 is in an emitter-follower configuration, so you get a diode drop down from the base to the emitter. This provides a coarsely regulated 13 V as the input for your LM317 regulator.
And now the down side: you're not really saving any power consumption here, you're just sharing the power dissipation between Q1 and LM317. At a 35V input and your maximum 200 mA, there will be a 22 V drop across Q1, and an 8 V drop across U1. Power is current times voltage, and Q1 is dissipating 4.4 W (HOT!!!) and U1 is now only dissipating 1.6 W. Before, U1 was dissipating all of that power (6 W), so it is definitely running cooler.
This brings up an issue with your part selection - the PZT2222AT1 is a low-power transistor. Under optimal conditions, its absolute maximum power is 0.6 W. You have now shifted the issue from your regulator to the pre-regulator transistor. I would recommend a switching regulator (buck converter) instead of a linear regulator approach, and that would dissipate much less power due to the higher efficiency.