In 1932 Ferris and Klyver described the species Psylla apicalis, the first known psyllid feeding on Sophora, but noted that it varied widely in its wing patterns and coloration, to a degree consistent with two separate taxa—although the authors believed it was a single variable species.

[1] A 2018 genetic analysis of New Zealand Psylla suggested there could be five undescribed species in the genus, including potentially two found on South Island Sophora microphylla.

[3] Specimens were collected from S. microphylla (the most common kōwhai species) in 21 locations around the South Island.

Much of the cinema trilogy The Lord of the Rings was shot in the South Island, where this species is found.

[4] P. frodobagginsi is smaller than its close relative, P. apicalis, lighter coloured, and has spotted wings.