Next to the royal mayfly, the caddisfly is typically the second most important aquatic insect for the fly fisherman.
As with mayflies, caddisflies has multiple life stages and all but the egg stage are important to fly fishers. For more information on the caddisfly life stages please see the caddisfly section under entomology here...
With respect to color, the vast majority of caddisflies are various shades of either brown or green. Hook sizes will range between #12 and #18 with #14-16 being most common. As with all dry flies, tying with the correct body proportions will increase the effectiveness of your fly (see caddis proportion image on the right).
Having almost always fished waters that support large caddis populations, I have developed a preference for three particular caddisfly patterns. They are the spent partridge caddis, the elk hair caddis and the Lawson "electric" caddis pupae. Videos for all three can be found below. I especially like the spent partridge caddis early and late in the day fished to sit very low in the surface film...so little or no floatant. The elk hair caddis is a favorite on faster water and the Lawson "electric" caddis is my preferred caddis pattern early in an anticipated caddis hatch. I am guessing the the Lawson caddis is based on several of the caddis pupae patterns designed and made famous by Gary LaFontaine...they were very close friends.
Articles and videos on tying caddisflies:
I cannot say enough about how good this series of video are. They mix entomology with fly tying...