Bizarre transistor behavior and voltage with DC motor in simple circuit
According to second image transistor seems to be connected in oposite direction (switched Collector with Emitter). It means common collector configuration is used instead common emitter and it's usually not enough to drive motor. And C-E can handle only about 10V Max (more or less, depends on transistor) even if it could handle much more in oposite direction.

See link for more details:


  
  Common Base Configuration   –   has Voltage Gain but no Current Gain.
  Common Emitter Configuration   –   has both Current and Voltage Gain.
  Common Collector Configuration   –   has Current Gain but no Voltage Gain.
  


I've just tested this circuit an it must be powered by power jack. USB is not strong enough.