192 MISCELLANEA. [18/4. 



their odour ; but this cannot have been the case, and I have 

 often fancied that they must have some common signal. 

 Your last chapter is one great mass of wonderful facts and 

 suggestions, and the whole profoundly interesting. I have 

 seldom been more gratified than by [your] honourable mention 

 of my work. 



I should like to tell you one little observation which I 

 made with care many years ago ; I saw ants (Formica rufa) 

 carrying cocoons from a nest which was the largest I ever saw 

 and which was well known to all the country people near, and 

 an old man, apparently about eighty years of age, told me 

 that he had known it ever since he was a boy. The ants 

 carrying the cocoons did not appear to be emigrating ; 

 following the line, I saw many ascending a tall fir-tree still 

 carrying their cocoons. But when I looked closely I found 

 that all the cocoons were empty cases. This astonished me, 

 and next day I got a man to observe with me, and we again 

 saw ants bringing empty cocoons out of the nest ; each of us 

 fixed on one ant and slowly followed it, and repeated the 

 observation on many others. We thus found that some ants 

 soon dropped their empty cocoons ; others carried them for 

 many yards, as much as thirty paces, and others carried them 

 high up the fir-tree out of sight. Now here I think we have 

 one instinct in contest with another and mistaken one. The 

 first instinct being to carry the empty cocoons out of the nest, 

 and it would have been sufficient to have laid them on the 

 heap of rubbish, as the first breath of wind would have blown 

 them away. And then came in the contest with the other 

 very powerful instinct of preserving and carrying their 

 cocoons as long as possible ; and this they could not help 

 doing although the cocoons were empty. According as the 

 one or other instinct was the stronger in each individual ant, 

 so did it carry the empty cocoon to a greater or less distance. 

 If this little observation should ever prove of any use to you, 

 you are quite at liberty to use it. Again thanking you 



