ANNALS OF SCOTTISH NATURAL HISTORY 



September, when very fine warm weather was experienced. This 

 suddenly ended on ist October; the mean temperature for that 

 day being 48.1 F., and only 26.8 on 2nd October, there being a 

 fall of 30 in twenty-nine hours. Very heavy snow fell, and the 

 summit has not been clear since. 1 In September I went down 

 to the Low Level Station, and, except for one week, did not return 

 to the summit until iQth November; so that since August I 

 have practically collected nothing. I will therefore give a brief 

 abstract of the weather of May and June and of July and August, 

 and these will show some rather striking results when compared 

 with the collections. 



May and June. 



i. There were 288 hours of sun- 

 shine, being 55 above the mean. 



2. The percentage of cloud was 6/ 

 below the mean, being 72.5^. 



3. The mean temperature was 2 J 

 above the mean. 



4. The rainfall was only slightly 

 above half the mean. 



5. In May the wind force was 

 slightly above the mean, but in June 

 only about one-third the mean. 



Juty and August. 



1. There were 49 hours of sun- 

 shine, being 77 below the mean by 

 far the lowest amount ever recorded 

 on Ben Nevis for these months. 



2. The percentage of cloud was 

 6. 5"/ above the mean, being 94-5/r- 



3. The mean temperature was nor- 

 mal. 



4. The rainfall was only slightly 

 above the normal, but rain fell on 59 

 days out of the 62. 



5. The wind was slightly above the 

 mean. 



The greatest number of insects seen during the summer was 

 probably on the 6th of June. Taking squares on the snow measur- 

 ing 2x2 feet, I calculated that there must be many hundreds of living 

 insects on each such square. Now on the 23rd May I marked out 

 nine such squares and counted all the insects within them. There 

 was an average of 29 in each, 6 of which were dead, and only i 

 of which was not an Aphis. Therefore there must have been about 

 400,000 Aphides upon the summit on that day. Think of the varied 

 myriads that there must have been on the 6th of June ! On that day 

 a small hand basin of water which had been standing outside near 

 the Observatory for not more than thirty -six hours contained at 

 least 300 flies, etc. The mountain top was buzzing with life. I 

 was especially busy that day, and could not do much collecting. 

 Had I collected on that day alone I could have captured thousands 

 (literally) of insects ! All these insects are not indigenous to the 

 mountain top, but must be carried up by warm currents. It is in 

 the neighbourhood of the First and Second Gorges that insects are 

 most plentiful, and they are doubtless swept up by the strong 

 draughts peculiar to these gullies. Among other species I saw a 

 small Tortoise-shell Butterfly. 



1 Snow fell during every month in 1895 except September. 



