- Recently the black windmill butterfly Byasa crassipes in Arunachal Pradesh’s Dibang Valley in the Lower Dihang Valley district was found.
- So far the butterfly has been mentioned only in two books: the 10-volume Lepidoptera Indica, a book on India’s butterflies by the East India Company’s Frederic Moore in 1913, and The Fauna of British India written in 1939 by George Talbot.
- The butterfly has not been recorded in India ever since.
- It was a seven-hour-trek to sight a rare bird in the wild that led nature enthusiast David Raju to the even more uncommon scarce siren butterfly Hestina nicevillei in the Daranghati Wildlife Sanctuary in Himachal Pradesh in 2012.
- The species was being photographed for the first time in history, and being sighted for the first time in India since 1917.
- Both butterfly species are listed under Schedule I of India’s Wildlife Protection Act (1972), which ensures the insects the same protection as that given to tigers.
- Locations of butterfly sightings are usually made public in the Butterflies of India where both the species’ rediscoveries have currently been listed.
- The frosted duskywing Erynnis pelias – recorded only from south-eastern Tibet and western China till now – in Anjaw district in Arunachal Pradesh.