Colonel Walker also had much greater success with flies dressed with the wings in the natural position than with any others. In fact, for several consecutive days, on different occasions he caught no fish except with my flies, though he did not use them more than flies dressed in the ordinary way.
Several other fishermen have told me that their experiments with my imitations have produced similar results.
Mr. H. H. Brown, of the Piscatorial Society, after I had read a paper to that Society on my theory of the right way to dress trout flies, described a very interesting experience which he had one day when out fishing, and which bears directly on this theory. While out fishing some time ago, he rested on a bridge over the river in which he was fishing. There were a great number of Alders about, and on observing some fish in the water some little distance below the bridge, he caught some Alders, pinched their heads slightly in order to either kill them outright or at any rate stop them struggling, and threw them on the water. He was in such a position that he could observe each fly individually until it either floated past or was taken by the fish. What he observed was, that when in killing the fly he had disturbed the natural position of the wings, not one of the fish would look at it; while, if the wings remained in the normal position of rest, the fly was always taken. This occurred time after time, and not once was the fly with the wings in an unnatural position taken, but, on the other hand, not a single fly with its wings in the natural position of rest was allowed to pass. He also observed that once or twice the fish came up to look at a fly whose wings had been disarranged, but on getting close to it they always drew back.
This is, I think, an extremely strong argument in favour of my theory.
I do not propose in this work to deal with Ephemeridæ, as the wings in the imitations now sold are in the natural position. The families I do propose dealing with are the Sialidæ, Trichoptera, Diptera, and Perlidæ, as no one has yet, to my knowledge, described the position in which the wings of the imitations of these flies should be put.
CHAPTER II
Colour Perception in Fish
(Rewritten from “Land and Water,” November 6, 1897)
Many interesting problems constantly come before the fisherman, but certainly one of the most interesting which has recently attracted his attention is Sir Herbert Maxwell’s theory on the power of fish to discriminate between various colours.