G. V. Hudson. — The Entumologij of 2Iount ArUiur. 185 



this locality may be of some interest, as showing the range of 

 altitude exhibited by many species. Amongst the butterflies, 

 Vanessa goncrilla and ChrysopJianus sahistius were occa- 

 sionally met wdth at about 3,200ft. They did not exhibit any 

 noticeable divergence from the type. Agrotis nullifcva ^yas 

 once taken at light, also Scoparia diplitheralis, both being 

 normal forms. Cramhus Jlextioselhis, Boarmia productata, and 

 B. melinata occurred occasionally from 2,000ft. to 3,500ft., but 

 were not very common. In all the specimens the markings 

 were somewhat darker than usual. 



Petalura carovei, the great dragon-fly of New Zealand, was 

 very abundant in swampy localities round Salisbury's Opening. 

 I did not see any specimens above 4,000ft., while the smaller 

 Libcllula smitlii, Agrion colcnsonis, and A. zcalandica were 

 swarming almost everywhere, extending up to the top of the 

 mountain. The ordinary flesh-flies {Calliphora guadrimacu- 

 lata, Sarcop)haga lamica, Sec.) were, as usual, everywhere. _ I 

 noticed many specimens on the top of Mount Arthur while 

 eating my lunch. I am quite at a loss to understand what 

 supports such large numbers of these insects in such remote 

 localities, and can only conjecture that they are endowed with 

 an extremely keen sense of smell, and travel great distances 

 in search of food. 



Among Coleoptera, Pyroiiota /estiva was everywhere abun- 

 dant, and was perhaps slightly larger and more brilliant in 

 colouring than the ordinary form, although I think specifically 

 identical. CeratognatJms foveolatus occurred under the bark 

 of the mountain-birch ; but, as I have before mentioned, I did 

 not devote sufficient time to this order to judge at all accu- 

 rately of its prevalence. 



An inspection of the insects taken, arranged according to 

 the elevation at which they occurred, will, I think, at once 

 show that as the mountains are ascended the Lcpidoptera 

 become decidedly darker in colour. This has long been ob- 

 served in other countries, but I think it is interesting to be 

 able to contribute further evidence from New Zealand. Ee- 

 specting the cause of this peculiar phenomenon, there seems 

 to be little doubt that it is owing to the low temperature exist- 

 ing at high altitudes, as the same effect has been produced 

 artificially by retarding, by means of an icehouse, the develop- 

 ment of three species of European moths {Selcnia illiistraria, 

 illunaria, and alniaria), of which Mr. Merrifield gives a most 

 interesting account in the "Transactions" of the Entomological 

 Society for 1889. Lord Walsingham has long ago suggested that 

 a darker colouring, or melanism, is advantageous to alpine and 

 arctic insects, as it enables them to absorb the sun's rays much 

 more rapidly than if they were of a lighter hue ; and he 

 instances, as an example, the simultaneous emergence of a 



