A very nice acquisition indeed ! Spot on specimen...
I had a specimen in my collection for a few years which was acquired from an old collection. However, a collector friend visited one day and (had to have it) so, he made me a trade offer I could not refuse.
I'll probably never find another one but, then after all we are only really caretakers of our treasures and they must pass into the hands of others to enjoy someday...
Papilio elwesi has flamboyant hind wings like that. I take it the two must be taxonomically related. Can you elaborate Adam ?
P.elwesi comes from China and Vietnam. A. maraho is endemic to Taiwan.
I do know that the two species have such dilated tails that two veins are needed to support them (unlike all other papilio).
Also, is it more correct to call both as Papilio .... or as Agehana .... since Agehana is a considered a subgenus ?
P. elwesi and maraho are very closely related, either sister species or subspecies of the same species. A Taiwanese researcher told me that the main reason they are considered to be separate species is political rather than scientific.
It is worth pointing out that the reason that these butterflies have 2 veins in their 'tails' is that they are actually tailless species with an elongate hindwing that mimics the tails of Byasa polyeuctes. They don't have true tails, which are an extension of a single vein.
P. elwesi has 2 forms, with and without a white patch on the hindwing, and the distribution of the forms mirrors polyeuctes. In much of China that species lacks a white patch, so elwesi also has a white patch. This form is known as form cavalieri, and is rare in China compared to the dark form. In Hagiang, the northernmost province of Vietnam where elwesi is also found, both species have a white patch on the hindwings. Hagiang is the only part of Vietnam that elwesi occurs, even though B. polyeuctes is found across the country. Almost certainly elwesi is restricted by the absence of the foodplant further south.
In reality Agehana is a subgenus of Papilio, but if other subgenera, such as Chilasa, are treated as genera then to be consistent that should be treated as a genus too. There is a big disadvantage in splitting genera unnecessarily, as non-taxonomists will not realise that actually the different genera are related. it is better to call them Papilio subgenus x, y or z. P. maraho can be called Papilio (Agehana) maraho if the subgenus needs to be indicated. That way people seeing the name along with Papilio (Agehana) P. elwesi will know they are related.