ILLUSTRATIVE OF NATURAL SELECTION, 151 
to the well-known P. Erechtheus, of Australia. The 
most common form of the female also resembles that 
of P. Erechtheus; but a totally different-looking in- 
sect was found by myself in the Aru Islands, and 
figured by Mr. Hewitson under the name of P. Ones- 
imus, which subsequent observation has convinced me 
is a second form of the female of P. Ormenus. Com- 
parison of this with Boisduval’s description of P. 
Amanga, a specimen of which from New Guinea is 
in the Paris Museum, shows the latter to be a closely 
similar form; and two other specimens were obtained 
by myself, one in the island of Goram and the other in 
Waigiou, all evidently local modifications of the same 
form. In each of these localities males and ordinary 
females of P. Ormenus were also found. So far there 
is no evidence that these light-coloured insects are 
not females of a distinct species, the males of which 
have not been discovered. But two facts have con- 
vinced me this is not the case. At Dorey, in New 
Guinea, where males and ordinary females closely 
allied to P. Ormenus occur (but which seem to me 
worthy of being separated as a distinct species), I 
found one of these light-coloured females closely fol- 
lowed in her flight by three males, exactly in the same 
manner as occurs (and, I believe, occurs only) with 
the sexes of the same species. After watching them 
a considerable time, I captured the whole of them, and 
became satisfied that I had discovered the true rela- 
tions of this anomalous form. The next year I had 
corroborative proof of the correctness of this opinion 
