While fishing in a water where the trout are very numerous in the spring of 1897, I found that I could hardly catch a single trout in the day with the fly. The weather was cold and windy, and showed no signs of mending. At last, one day, I opened a trout, one of the few that I had caught during my visit, and found the stomach full of some insects belonging to the family of CorixÆ. These insects are very commonly called Water Beetles, or Water Boatmen. They, however, are not beetles but bugs (Heteroptera), and are not the same as the true water-boatmen, the Notonecta glauca, though they somewhat resemble it in appearance.

On finding these insects in the trout I took some of them home, and made imitations of them. With these the next day I caught a number of trout, though the weather was just as unfavourable. Since then I have improved somewhat upon the imitations I then used, and in waters which are inhabited by CorixÆ. These imitations have met, both in my hands and in the hands of others, with greater success than any other form of wet fly.

It is an extraordinary thing, considering the number of men who have written on trout fishing, that it has apparently never occurred to one of them to describe an imitation of one of this large family of insects. Mr. Halford, in his Dry-fly Entomology, indeed states that he has frequently found them in the stomachs of trout, but he does not even suggest that an imitation of them might be made.

There are many species of CorixÆ which inhabit our waters, but the commoner sorts are so similar in appearance that many of the species are very difficult to distinguish even by an expert, and but little work has been done with regard to them. Therefore I have come to the conclusion that a similar dressing on different sized hooks will be quite sufficient to deceive the unscientific eye of the trout. This conclusion is corroborated by the fact that I have several times had an imitation Corixa seized by a trout when it was sinking, and before I began to draw it through the water, which is, I take it, a fairly severe test as to the accuracy of the imitation. Colonel Walker and Mr. Herbert Ash have also had the same thing happen to them when fishing with my imitation CorixÆ.

CorixÆ vary much in size, the largest and one of the commonest species being the Corixa geoffroyi, which is about half an inch long. In all CorixÆ, the head is wide and is attached but slightly to the body. It is convex in front and concave behind, so as to fit the end of the thorax, and is as wide as the wings when folded and at rest. These insects possess four wings, which they frequently use, though they are somewhat clumsy in starting from the surface of the water. I have sometimes, however, seen them fly considerable distances. The anterior wings resemble the wing-cases of a beetle; they are hard and shiny, brown in colour, with dark mottled markings upon them. The posterior pair are transparent. The abdomen is light yellow and fringed with hairs, and there are transverse lines on the dorsal surface of the thorax. As, however, these markings on the thorax and wings are hardly visible to the naked eye, they give the Corixa a generally brownish and shiny appearance. Of the legs, six in number, the hind pair are most used in swimming. They are somewhat flattened at their extremities to a paddle shape, and are fringed with hairs. I have seen the hind legs of the CorixÆ when the insects have been suspended motionless in mid-water, standing out at right angles on each side of the body; and as in the imitation I am about to describe, the legs take this position when the fly is at rest or sinking in the water; this explains the fact of the trout taking them in the way I have mentioned above.

The Corixa sahlbergi, which is almost as common as the Corixa geoffroyi, is about half its size, but is otherwise very similar in appearance, as are nearly all the other smaller species.

The Corixa frequently comes to the surface to breathe, and a number of small air bubbles attach themselves to its body. These, when the insect is swimming under water, give its body a brilliant silvery appearance, with the yellow showing through in places. This effect is accurately reproduced by ribbing the body with silver tinsel.

The size of the hooks used must depend upon the size of the species of CorixÆ inhabiting the water to be fished, and varies from No. 1 to 3, new size.

The CorixÆ in any particular water may easily be found in order to observe the size. They congregate in great numbers among the weeds, &c., on the bottom of the water. They are very numerous in most millponds, pools, back-waters, sluggish waters and ponds.

The body is made with light yellow Berlin wool, teazed up with fur from the hare’s face, and ribbed with silver tinsel. A good space of shank should be left above the body.

The only legs which make any show in the water are the hind legs, and they are the only ones it is absolutely necessary to imitate; should, however, the fisherman wish to imitate the others, one turn of a ginger hackle may be used.

When I described the Corixa in the Field I directed that the hind legs should be made with a strand of peacock herle. I have however found a better imitation of these legs since then, in the end of a quill feather from a starling’s wing. This keeps up its spring even when soaked for a long period in the water, while the peacock herle legs after a time adhered to the body of the fly, and did not stand out on each side when the fly was at rest. The tip of the feather should be completely cleared of fibres on one side, and nearly so on the other, leaving however a few short stumps at the end, as shown in illustrations of imitation in Plate III., to represent the paddle-shape of the legs. These legs are then tied in at right angles to the body. I have found the best way of accomplishing this is to tie the legs in straight to the side, with the buts pointing towards the tail of the fly. Then bend them down, and put enough turns of the tying silk round the shank of the hook to keep them in the position shown in the illustration of the imitation.

The wings are made from the quill feathers of the woodcock, laid flat on the body one over the other, as described in the directions for tying PerlidÆ, which have their wings lying one over the other. The head must be made large, and the whole fly when finished appear as shown in the illustration.

When used, this fly should be allowed to sink. The depth to which it must sink varying according to circumstances, and then drawn through the water in little jerks. Each of these movements through the water causes the legs, which stand out on each side of the body, to bend back; but at the end of the jerk, when the fly is momentarily stationary, these legs resume their original position. Thus the movement of the legs of the natural insect when swimming is accurately imitated. (June 12, 1897.)

This imitation Corixa has met with a very general condemnation as not being a lure which should be allowed on waters where the use of the fly only is permitted. As this child of my fancy has cost me many hours of careful thought and labour, I am inclined, with all due deference to these opinions, expressed by men of much greater experience than mine, to say a few words in its defence.

CorixÆ are insects which live in the water and are eaten by trout. They possess wings which they use frequently, sometimes flying a considerable distance, and I have seen trout take them just as they were trying to leave the surface of the water. The efficacy of the imitation, therefore, depends upon the skill of the fisherman, who must make it simulate in its movements the movements of the natural insect. Mr. G. A. B. Dewar, in his Book of the Dry Fly, in speaking of “tailing” trout, which are probably feeding on "food of the shrimp and snail order,“ advises that they should be fished for "with a long line down stream, and the fly worked with a series of little jerks, somewhat as in salmon-fishing. The fly should be cast just above where the head of the trout is adjudged to be, and worked into the angler’s bank, and it must never be kept still, otherwise the fish will at once perceive the deception and at once decline it.” Mr. Dewar then mentions a dry-fly angler of great skill who is very successful in fishing in this manner with a big Alder. It is more than probable that in these cases the Alder is taken for a Corixa, or something very like it, as the colour, size, and movements are somewhat similar.

The Marquis of Granby, in the preface to Mr. Dewar’s book, also speaks highly of a sunk alder for “tailing” trout.

“To kill ‘tailers’ in broad daylight and in low water is quite an art in itself,” is another quotation from The Book of the Dry Fly upon this mode of fishing, and though the author points out that this is not true dry-fly fishing, still if the fisherman’s conscience allows him to use a sunk Alder down stream and worked in this manner, I think it should also allow him to use an imitation Corixa under similar circumstances.

I should not have dragged the writings of others into such a question as this, had not the criticisms upon my flies been an indirect attack upon myself, as what has been said about them practically means that they ought not to be used by any one who calls himself a sportsman. If this is true of the flies, what could not be said of their inventor? For this reason I take the best means I can find to defend myself, and what better defence could there be than the published practices of two men whose sportsmanlike qualities have never been doubted?

What is legitimate trout-fly has, I believe, never been clearly defined; but I hope I shall not be presuming too much in saying, that if the lure in question is the imitation of an insect which can and does fly, made of the ordinary materials used in fly-making upon one hook, this lure has a perfect right to be called a legitimate trout-fly.

It will be found that my Corixa fulfils these conditions.

There is one thing that I wish particularly to impress upon my reader, and this is that, in using the imitations of CorixÆ and Fresh-water Shrimps, he should find out whether these creatures inhabit the water he is fishing. If he does not do this and fishes with the imitations of either of them where they do not exist, he will probably meet with failure and disappointment.