AND INTRODUCED FAUNAS 515 



an interesting remark on the colour changes in introduced animals, 

 to this effect: 



The strong insolation of the area, is, I think, affecting the colour of the 

 wild animals, goats, pigs and rabbits. Where the normal colour is khaki, 

 as in rabbits, melanism is very frequent, but in the Clarence valley, 

 bicoloration is common. This in a pig makes for better concealment. 

 I noticed this particularly. A huge spotted boar running on a hillside 

 about a mile away was conspicuous owing to his movement, but he dis- 

 appeared as soon as he stopped. 



Seasonal changes common to certain species in the Northern 

 Hemisphere tend to be reproduced in New Zealand, wherever the 

 climatal changes correspond. Thus in the colder parts of Canterbury 

 and Otago, where severe winter frosts are often experienced, hares, 

 stoats and weasels tend to grow white winter coats. But I have no 

 record of such changes occurring in the warmer districts. 



The introduction of stoats and weasels, which was undertaken 

 primarily as an antidote to the rabbit pest, has had other far-reaching 

 consequences on the introduced fauna. It has certainly helped to 

 prevent the establishment of such species of bijds as partridges, 

 ducks and other game birds ; and it has probably also greatly reduced 

 the reproduction and spread of well-established birds like pheasants. 

 On the other hand it has enormously reduced the numbers of rats and 

 mice in the country, and in this way may have indirectly helped in 

 the preservation of the native weka (Ocydromus), and the Calif or nian 

 quail, both of which appear to have increased of late years, in districts 

 where stoats and weasels are quite common. Probably also the humble- 

 bees have benefited by the destruction of mice. 



It might be thought that the reversal of the breeding season 

 between the northern and southern hemispheres might affect intro- 

 duced species, but no such changes have been recorded. With intro- 

 duced individuals it might be noticeable. I am informed by bird 

 fanciers and dealers that some introduced birds suffer very seriously 

 at the moulting season. This is particularly the case with imported 

 canaries; but these are highly artificial and domesticated birds. 



Scarcely any attention has been paid to the relations between 

 introduced animals and plants and indigenous species. It is, however, 

 probable that native ichneumon flies have found suitable hosts in 

 several species of introduced insects, but no one seems to have kept 

 any definite record of the facts, if they have occurred. 



One definite example has been frequently reported. A native lady- 

 bird — Coccinella tasmanii. White — which is common in both islands, 

 has been found to be very destructive to melons, cucumbers, etc., 

 and also to Schizoneura langigera, Haus., the woolly aphis. 



33—2 



