Fereday. —On Percnodaimon pluto. 



197 



Art. XX. — Note on a peculiar Neuration in the Wings of some Individuals of 



Percnodaimon pluto, a New Zealand Butterfly. 



By E. W. Fereday, M.E.S.L. 



[Read before the Philosophical Institute of Canterbury, 30th November, 1882.] 



When examining some specimens of P. pluto I noticed that the costal 



nervure of the primary wings of one of them was bent inwards and united 



to the first subcostal nervule, the united nervure and nervule running 



thence in one vein to the anterior margin, as shown in the annexed 



diagram, fig. la. In ordinary speci- 

 mens the first subcostal nervule is 

 not present, and the costal nervure 

 is of the ordinary form as shown in 

 the annexed diagram, fig. 2. (The 

 diagram is twice the natural size of 

 the wing). 



The discovery of this peculiarity 

 led me to examine very carefully 

 all the specimens of P. pluto in my 

 collection, and those in the collec- 

 tion of Mr. J. D. Enys. These 

 collections consist of 33 specimens 

 taken on a mountain near Mr. 

 Enys' station, Castle Hill, Porter's 

 Pass, 21 on Mount Hutt, and 1 on a mountain near Lake Guyon (Nelson 

 Provincial District). Six males and one female of the Castle Hill speci- 

 mens, four males of the Mount Hutt, and the one male of Lake Guyon, 

 have the united veins, and are smaller, but in other respects do not appear 

 to differ from the ordinary form. In all the specimens having the united 

 veins, such veins are alike in form, position, strength, and point of junc- 

 tion, and all the other veins are uniform with those of the ordinary speci- 

 mens. No other irregularity of neuration appears in any of the specimens, 

 nor does there appear to be any other tendency to variation in the species. 



Does the neuration of the wings of Le\ndoptera furnish a reliable char- 

 acter for determining families and genera ? I will not attempt to answer 

 this question, but I submit the above facts for the consideration of ento- 

 mologists. 



