﻿54 THE ENTOMOLOGIST. 



Perhaps a few notes on the low-land insects observed in this 

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

 exhibited by many species. Amongst the butterflies, Vanessa 

 gonerilla and Chrysophanus salustius were occasionally met with 

 at about 3200 feet ; they did not exhibit any noticeable divergence 

 from the type. Agrotis nullifera was once taken at light, also 

 Scoparia diptheralis, both being normal forms. Crambus flexuo- 

 sellus, Boarmia productata, and B. melinata occurred occasionally 

 from 2000 to 3500 feet, but were not very common ; in all the 

 specimens the markings were somewhat darker than usual. 



Petalura carovei, the great dragonfly of New Zealand, was very 

 abundant in swampy localities round Salisbury's Opening. I did 

 not see any specimens above 4000 feet, while the smaller Libellula 

 smithii, Agrion colensonis, and A. zealandica were swarming almost 

 everywhere, extending up to the top of the mountain. The 

 ordinary flesh-flies (Calliphora quadrimaculata, Sarcophaga 

 lesmica, &c.) were, as usual, everywhere. I noticed many speci- 

 mens 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, Pyronota f estiva was everywhere abundant, 

 and was perhaps slightly larger and more brilliant in colouring 

 than the ordinary form, although I think specifically identical. 

 Ceratognathus 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 accurately 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 Lepidoptera become decidedly 

 darker in colour. This has long been observed in other countries, 

 but I think it is interesting to be able to contribute farther 

 evidence from New Zealand. Respecting the cause of this 

 peculiar phenomenon, there seems to be little doubt that it is 

 owing to the low temperature existing at high altitudes, as the 

 same effect has been produced artificially by retarding, by means 

 of an ice-house, the development of three species of European 

 moths {Selenia illustraria, S. itlunaria, and S. alniaria), of which 

 Mr. Merrifield gives a most interesting account in the ' Trans- 

 actions of the Entomological Society for 1889.' Lord Walsingham 

 has long ago suggested that a darker colouring or melanism is 

 advantageous to alpine or 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 white and a black insect from the pupa in a stormy 

 and cold climate, such as we have in the alpine regions. A passing 



