This species was first described in 1948 by John T. Salmon as Porina unimaculata from specimens collected by Graham Turbott on the Three Kings Islands.

[4] John Dugdale created the genus Dumbletonius in 1986,[5] and moved this species into it in 1994, synonymising Dumbletomius sylvicola with it in the process.

[2] The bright colouration of the hindwing of the male of the species fades rapidly after death.

[6] Dumbletonius unimaculatus is endemic to New Zealand[7] and can be found only in the North Island where it is regarded as being common.

[8] Larvae live two to three years in tunnels amongst the leaf litter and can grow to a length of 10 cm.