The San Juan Worm is a divisive fly. Some love fishing with it, others think its an abomination. However no one can deny its effectiveness in certain situations. The traditional way of tying these is to just tie the chenille in two points, and not wrap around the hook, however I find wrapping it makes it look more like an earthworm, and gives it more durability and less chance to spin around the hook shank.
This fly is one of the more easy to tie flies. It requires very little materials, and you can fill a box in a short amount of time. Once you get in a grove, you can pump these out in very little time. I have tied up to 30 in an hour, even with this style which takes just slightly longer than the traditional San Juan Worm. You can also tie these in a number of different colors. I know people who fish them in white, red (like you see here and most common), olive, black, brown, pink, chartreuse and much much more.