Bassarona durga
Bassarona durga, the blue duke, is a species of nymphalid butterfly found in the Himalayas. Range
It is found in Sikkim, Abor Hills and Nagaland. In June 2022, it was declared as the State Butterfly of Sikkim. References

Durga
Butterflies of Asia
Fauna of the Himalayas
Insects of Bhutan
Insects of Nepal
Fauna of Tibet
Butterflies described in 1857