78 OLD FLIES IN NEW DRESSES 



pillars, most of these caterpillars being of 

 a brilliant emerald green colour. 



In the afternoon of the clay on which I 

 am writing this, Colonel Walker showed 

 me a peculiar sort of knife which he carries 

 when out fishing, for the purpose of mak- 

 ing autopsies on trout. I naturally took ad- 

 vantage of this occasion to increase my 

 evidence, and asked him if he had ever 

 found caterpillars in the trout he caught. 

 He told me that in certain places, in the 

 early part of the summer, he almost always 

 found caterpillars in the stomachs of the 

 trout he caught under trees overhanging 

 the water. 



This experience of his exactly coincides 

 with my own, though the six consecutive 

 autopsies described above without my 

 other similar experiences is a fairly strong 

 piece of evidence. I am therefore inclined 

 to believe that there is some good to 

 be gained in following the sapient advice, 

 verbal and written, to cultivate vegetation 

 overhanging the river, beyond its advan- 

 tage as giving shelter to the fish. 



I will narrate the circumstances which 

 first led me to use the caterpillar as a 



