1895.] L. de Niceville & Dr. L. Martin — Butterflies of Sumatra. 511 
574. Papilio ( Menelaides) deli anus, Pruhstorfer. 
P. doubledayi , Wallace, var. dehanus , Fruhstorfer, Ent. Nach., yoI. xxi, p. 196 
(1895). 
Hagen as doubledayi. Originally described from Deli in Sumatra. 
Wallace gives P. coon, Fabricius, from Sumatra, Java, and Borneo, 
and says that P. doubledayi, Wallace, the Indian form, differs from it 
in having the markings red instead of yellow. The Sumatran form 
in both sexes has the markings at the anal angle of the hindwino* dis¬ 
tinctly red, while P. coon from Java has them equally distinctly yellow. 
The abdomen of our Sumatran examples is, however, more yellow than red. 
We have thus true P. coon occurring in Sumatra, and also an interme¬ 
diate form between that species and the continental P. doubledayi, shew¬ 
ing the exact region where the one species is gradually becoming trans¬ 
formed into the other. P. delianus is rare in the forests of the plains and 
outer hills, is found at Selesseh, Namoe Oekor, and as high only as 
Bekantschan. It chiefly frequents the flowers of high trees and so is 
seldom caught. It has a fluttering but quick flight. Dr. Martin has 
specimens from so far south as Asahan. Rothschild does not allow 
P. delianus full specific rank, but records it is P. coon, Fabricius, ( d), 
P. doubledayi delianus, Fruhstorfer. 
575. Papilio ( Menelaides ) neptunus, Guerin. 
Hagen as neptunus, var. sumatrana, Hagen. The Malayan Penin¬ 
sula form of P. neptunus as figured by Distant has four crimson spots 
on both sides of the hindwing in the male, while the Sumatran form 
has only two; the female has three spots on both sides in the Malayan 
Peninsula form, while the Sumatran has two on the upperside and 
three on the underside. In all other respects the species from these 
two localities agree as far as I can see. I have not seen specimens from 
Borneo, from whence P. neptunus is recorded by Wallace. It is certain¬ 
ly one of the remarkable butterflies of the world ; the anal half of the 
abdomen in both sexes being of a bright chrome-yellow colour is in 
unique and startling contrast to the rest of the black abdomen and the 
black wings with the crimson spots on the hindwing. No doubt this 
staring yellow-tipped abdomen serves as a very efficient danger-signal 
or warning-colour to the enemies of butterflies to leave this particular 
species severely alone, the butterfly being obviously a protected one 
and with a very strong scent. It is quite as rare as P. delianus, 
Fruhstorfer, and is found in the same localities. Its flight is very slow 
and sailing, always high in the air and out of reach of the net. It is 
almost impossible to obtain perfect specimens. Rothschild records this 
species from Sumatra as P. neptunus, Guerin, (a 2 ), ab. sumatranus, 
