A style of fly and style of fishing named after the River Clyde in Scotland. Google returns plenty of info on Clyde Style flies and fishing. Looks like several books on the subject as well, but appears to be originally regional to Scotland.
"Flies on right show the typical Clyde Style. Hooks are light wired body length no more than half the shank, hackle of hen or upland game bird, 1-2 turns only. Wings are tied upright & set at a "jaunty wee angle" Lightness of construction is the keyword & hooking properties are good. Other than a touch or two of tinsel sometimes, a lack of embellishment & a general more sombre hue is it's marque." taken from http://www.thehighlanderway.com/clyde_style_flies.html
Here are a few more informative links.
http://www.fishandfly.co.uk/bookrevs/clyde.html
http://www.amazon.com/Clyde-Style-Fl.../dp/0715353527
http://www.anglersholidaycottages.co...ex11111111.htm
All that from typing "clyde style flies" in the Google search bar. So easy even a caveman can do it.