Bioluminescence in Nocturnal Millipedes (Motyxia)

In the Sierra Nevada Mountains of California, bioluminescent millipedes exist in eight nocturnal species of the genus Motyxia. The function of luminescence in Motyxia remains uncertain.

The essential question scientists are trying to answer is: Did luminescence evolve multiple times or just once? 

The figure below shows the phylogenetic tree of millipede taxa^[1].

Is this an example of convergent evolution or of a descended adaptation (conserved core process) from a direct common ancestor?

Place an arrow on the tree either showing a single origin or multiple origin for bioluminescence.

Bioluminescence in Fireflies

Fireflies (Coleoptera: Lampyridae) are one of the most common bioluminescent organisms in North America. One suggested benefits of firefly flashing is sexual selection by females who like longer flashes and specific patterns by males. One drawback to this is predatory fireflies will prey on males who flash too predictably or too long. Through these two constraints, there has been evolution of firefly signaling over time^[2].

The essential question is: Did bioluminescence evolve multiple times or just once in fireflies? 

Is this an example of convergent evolution or of a descended adaptation (conserved core process) from a direct common ancestor?

Place an arrow on the tree either showing a single origin or multiple origin for bioluminescence.