Hackle. Black.
Wings. As Red Ant.
Hook. 0—1.
CHAPTER IX
Caterpillars
“Of the caterpillars, spiders, and other creatures which are supposed to fall from the trees into the water, and into the trout’s mouth, and of the consequent advantage of trees projecting over a stream; of the sapient advice, both verbal and written, to cultivate vegetation overhanging the river, because it increases the supply of natural food; of the statement that fish under trees are invariably in the best condition, anglers have heard from time immemorial. My advice is, cultivate your trees, because they are of advantage as giving shelter to the fish. Not a single example of these tree windfalls has been found in the hundreds of autopsies which I have made, and all the caterpillars and spiders that fall from the trees in a mile of water would not suffice to feed a single pound trout for a single day. They may therefore be discarded from consideration.”—Halford’s Dry-fly Entomology, page 138.
I read this passage with extreme surprise, as it absolutely contradicts my personal experience. After thinking the matter over carefully, and trying to make out how it was that Mr. Halford, in the hundreds of autopsies he has made, has never come across a caterpillar, I realised how dangerous it is to make a dogmatic and sweeping statement with the evidence of personal experience only to fall back upon.
As recently as June, 1897, when fishing with Dr. Charles R. Watson and Mr. A. D. Home, I made with them a series of six autopsies of trout caught consecutively in one morning. The smallest number of caterpillars found in one of these six autopsies was five, and the greatest, twelve. These trout were all caught under oak trees overhanging the water, which were at that time swarming with small caterpillars, most of these caterpillars being of a brilliant emerald green colour.
In the afternoon of the day 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 making autopsies on trout. I naturally took advantage 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.