Original:  In practice, when no male heir is mature enough, a female heir is usually determined "pragmatically", by proximity to the last monarch, like Boariks of the Caucasian Huns or Tamiris of Massagetes in Middle Asia  .
Revised:  In practice, when no male heir is mature enough, a female heir is usually determined "pragmatically", by proximity to the last monarch, like Boariks of the Caucasian Huns or Tamiris of Massagetes in Middle Asia were selected .
Edit intent: clarity