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 BoisduvaPs 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 



