EuTLAND. — On the Neii- Zealand Bush-rat. 305 



inquiries immediately on my arrival, and obtained positive 

 evidence that the rats commenced making their appearance 

 there at the same time as they did in the Pelorus. Consider- 

 ing the geographical position of the two localities, I can hardly 

 see how this could take place if the animals came from the 

 more southerly portions of the Island. During the three 

 months the rats remain on the low lands of the bush country 

 they certainly have no appearance of travelling in any parti- 

 cular direction, but merely wander about like animals in quest 

 of food. 



In the early part of November, while the rats were so 

 numerous in the Pelorus Valley, one was observed evening 

 after evening for about three weeks coming out from among 

 the flowers in my garden, climbing a rose-tree that grows 

 against the verandah-post, and making his way along the wall- 

 plate to the roof of the building. This took place with such 

 regularity as to leave no doubt of its being the same individual. 

 I mention this as it plainly shows that these animals are not 

 always mere passers-by. 



It may now be very reasonably asked, "What, then, is the 

 cause of the periodical appearance of the bush-rats ? 



To this question I shall not attempt any definite reply, as 

 I do not consider the information at my command sufficient 

 to warrant my so doing. There are, however, certain circum- 

 stances which seem to suggest a solution of the problem ; and 

 to these I shall now refer. Generally, if not always, accom- 

 panying these rat-swarms are large iiocks of j)arroquets. On 

 the outskirts of the bush, as in Picton, the Tuamarina, &c., 

 these birds make their appearance a month or so later than 

 the rats ; but within the bush country they appear sinml- 

 taneously, or, if there is any difference in the dates of arrival, 

 the parroquets are first noticed. Although the parroquets 

 only appear here periodically in large mimbers, the bush is 

 never without them, and this remark is eqitally applicable to 

 the bush-rats ; though, owing to their habits and being less 

 conspicuous, they are not so generally observed. Every spring 

 a few of these little animals may be seen on the open tracts 

 ^vithin the bush country, and even during the twenty years 

 wherein no swarm took place in the Pelorus Valley they 'were 

 frequently observed, but not in sufficient numbers to attract 

 much attention. 



Another instance of the appearance in large numbers of 

 animals generally scarce is furnished by the mosquitoes of the 

 Pelorus Valley. A few of these troulDlesome insects are in- 

 variably found here throughout the warm season. Every now 

 and then immense swarms appear. These swarms, which 

 occur sometimes in spring, sometimes in autumn, are un- 

 doubtedly due to the occurrence of conditions favourable for 

 20 



