4Lines Blues, the Sanaya allies.

[Psyche]

The 4 -Line blues contain a number of closely similar species which seem near impossible to separate from the undersides.
Even the uppersides present great difficulties.

In Singapore three species are very closely similar in that the dark striaes within the postdiscal bands are typically absent and the HW black tornal spot lacks metallic scales.

They are Nacaduba sanaya, subperusia, and pendleburyi.
The keys gave ID difference based on the closeness of the HW submarginal spots & the postdiscal spots to one another, but this is very variable within each species.
From careful comparisons of valid images the IDs may be put thus.
SubperusSanaya.png

Nacaduba sanaya.
UnF postdiscal band often dislocated in upper third, vein 5, or 6 especially in the male.
UnH submarginal & postdiscal spots 4 & 5 usually well separated.
UnH submarginal spot 6 inner border drops gently to that of 5.
Female upperside often broadly light blue.
Males.
https://pamsbutterflies.com/butterfl...-sanaya-elioti
Females
Singapore.
https://www.butterflycircle.com/chec...race%20tan.jpg
https://www.butterflycircle.com/chec...drick%20ho.jpg
P.Malaysia.
https://www.flickr.com/photos/gancw1/14350846826


Nacaduba subperusia lysa.
(Ssp. lysa the lowland form differ from the highland ssp intricata.)
UnF postdiscal band much less likely to be dislocated.
UnH submarginal spots 4 & 5 more rounded & usually very close to the postdiscal band/spots.
UnH submarginal spot 6 large bulky, its inner border drop abruptly down to spot 5.
Male, female. Thailand.
https://thaibutterflies.com/Butterfl...uba-superusia/
Male. P.Malaysia.
https://3.bp.blogspot.com/-CCzm1ZlQs...rusia+lysa.jpg
https://www.gbif.org/occurrence/2847201282
Female. Cambodia.
https://geenature.com/taxa/animalia/...uba-subperusia
Current observations need good images for confirmation.



Nacaduba pendleburyi.
Similar to N. subperusia but marginal & submarginal spots in the male very narrow & the UnH submarginal spot 6 inner border drop less abruptly to spot 5 ..
UnH submarginal & postdiscal spots always widely separated.
Definitive ID. Male UpF dark border widens at apex.
Males.
https://www.gbif.org/occurrence/2847201385
https://www.gbif.org/occurrence/2847201401
Female.
https://yutaka.it-n.jp/lyc4/81191001.html
Added.
https://www.gbif.org/occurrence/2847201393
https://www.gbif.org/occurrence/2847201401

So far there seem no observation that is suggestive of this species.


Note the web is full of mis-IDs.
eg.
the UnH metallic scales on the black spot indicate it is N. hermus.
https://www.gbif.org/occurrence/2847200301
Female N. kurava.
https://www.gbif.org/occurrence/2847200298
Male should be N. hermus, female looks to be N. sanaya.
https://en.wikipedia.org/wiki/Nacadu...aMFUpUnAC1.jpg


TL Seow: Cheers.