This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
The standard selection of artificial flies numbers about 60, but the average fisherman will find about 24 selected patterns to answer every need. For making up the most "killing" flies for the trout season, the following can be recommended: Use red ibis, stone fly, cinnamon, red spinner, and parch-menee belle, for April; turkey brown, yellow dun, iron blue, spinner, mont-real and red fox, for May; spider, black gnat, silver doctor, gray drake, orange dun, and green drake, for June; July dun, grizzly king, pale evening dun, red ant, and brown palmer, for July; Seth green, coachman, shad, governor, August dun, and royal coachman, for August, and black palmer, willow, whirling dun, queen of the water, and blue bottle, for September.
To attach a line to the leader the well-known "angler's knot" is mostly used. This knot is shown at C. The snelled fly is attached by passing the loop over the loop of the leader and inserting the fly through the leader loop. When eyed flies are used they are often attached direct to the leader, or a looped snell may be used as in the ordinary American-tied fly. To attach the eyed fly direct to the leader, the common "jam knot," shown at D, is mostly used, and when the slipknot is drawn up tightly and the extra end cut off it makes a small, neat knot, not apt to slip.