Wikipedia
The Bukumiri are an extinct tribe of non- Slavic origin whose members populated parts of modern-day Montenegro. Together with other non-Slavic tribes of the region, since 6th century they were overwhelmed by Slavs who assimilated them but kept their name. Initially they were either Illyrians or Vlachs.
There are different hypothesis about etymology of Bukumiri. According to one of them, their name was derived from Albanian language ( means bread while means good), which is also an indication of their wealth.
According to legends, Španji are the most ancient tribe in this region, while other tribes ( Mataruge, Kriči, Bukumiri...) were actually parts of Španje tribe.
The Bukumiri lived in the region of Bratonožići tribe. For some reason they were despised by members of other tribes who refused to marry Bukumiri women. Over the time, they were assimilated by Bratonožići or extinct.