ILLUSTRATIVE OF NATURAL SELECTION. 183 



The Papilios which resemble them belong to a very 

 distinct section of the genus, in which the sexes differ 

 greatly ; and it is those females only which differ most 

 from the males, and which have already been alluded 

 to as exhibiting instances of dimorphism, which resem- 

 ble species of the other group. 



The resemblance of P. Romulus to P. Hector is, 

 in some specimens, very considerable, and has led to 

 the two species being placed following each other in 

 the British Museum Catalogues and by Mr. E. Double- 

 day. I have shown, however, that P. Romulus is 

 probably a dimorphic form of the female P. Pammon, 

 and belongs to a distinct section of the genus. 



The next pair, Papilio Theseus, and P. Antiphus, 

 have been united as one species both by De Haan 

 and in the British Museum Catalogues. The ordi- 

 nary variety of P. Theseus found in Java almost as 

 nearly resembles P. Diphilus, inhabiting the same 

 country. The most interesting case, however, is the 

 extreme female form of P. Memnon (figured by Cramer 

 under the name of P. Achates), which has acquired 

 the general form and markings of P. Coon, an insect 

 which differs from the ordinary male P. Memnon, 

 as much as any two species which can be chosen 

 in this extensive and highly varied genus; and, as 

 if to show that this resemblance is not accidental, 

 but is the result of law, when in India we find a 

 species closely allied to P. Coon, but with red instead 

 of yellow spots (P. Doubledayi), the corresponding 

 variety of P. Androgeus (P. Achates, Cramer, 182, 



